Ok, I've got 2 problems solved, (Thanks to Kainsworth, without who's help I wouldn't be this far !!), but here's my problem... I have the following:
Database name "Birdkeeper"
Table name "gentest"
OleDbConnection1
OleDbDataAdapter1
objDataSet1
DataView named "dvgentest"
Module with the following:
Friend f1 as DataForm1
Friend fs1 as frmsearch1
Friend dv as DataView
Friend ds1 as DataSet1
Fields named "Band", "Breed", and "Club"
there are 9 fields but was using these to get it working and add the others later.
Here is my code:
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

Dim dvgentest As New DataView(ds1.Tables_("gentest"), "", "Band, Breed, Club", DataViewRowState.CurrentRows)

Dim foundRows() As DataRowView = dvgentest.FindRows(New Object_() {"TextBox1.Text"})

If foundRows.Length = 0 Then
Console.WriteLine("No match found.")
Else
Dim myDRV As DataRowView
For Each myDRV In foundRows
Console.WriteLine("{0}, {1}, {2}", myDRV_("Band").ToString(), myDRV("Breed").ToString(), myDRV("Club").ToString())
Next
End If

Me.Close()

End Sub
I am trying to use a textbox on a search form to find any records that match the textbox and display them on the datagrid on the bottom form.
I have been able to do this using a specific field in the search (Thanx Ged !!), but when I try to use the above code to find any field, I get the following: "Object reference not set to an instance of an object". In reading the material that was recommended to me (Thanx again Ged !), the above seems to be the way to go but I know I'm making a stupid error somewhere and am not sure what the error code is trying to tell me. I have my DataView "ApplyDefaultSort" set to "True".
Any help would be greatly appreciated.
Bill

This message was edited by kainsworth at 2004-10-11 14:41:3

---

This message was edited by kainsworth at 2004-10-11 14:39:53

---

Bill,

I haven't succeeded yet in coming up with a fix that slots straight into your code as it stands. If it's any help, here's one way I came up with that allows you to analyze each row of a DataTable and if it finds a match in any column it adds that row to a new DataTable. Once it has gone through all the rows of the original table, the DataGrid is refreshed with the DataTable that now holds the search matches.

In this example:
DSOriginal is the DataSet holding the original data.
I hope that the commenting explains enough as to how it works.

  '  To start with, show original table in DataGrid
        Dim DTOriginal As DataTable = DSOriginal.Tables(0)
        DataGrid1.DataSource = DTOriginal

        '  Create new EMPTY DataTable by cloning structure of original
        Dim DTCloned As DataTable = DTOriginal.Clone

        '  Import the matching DataRows into the cloned Table
        Dim drtemp As DataRow
        Dim j As Integer
        ' Enumerate through all rows
        For Each drtemp In DTOriginal.Rows
            '  and within each row iterate through all columns
            For j = 0 To DTOriginal.Columns.Count - 1
                '  If you find a match ..
                If drtemp.Item(j) = Me.txtSearch.Text Then
                    '  add this row to the new DataTable
                    DTCloned.ImportRow(drtemp)
                    '  and stop looking along this row
                    Exit For
                End If
            Next
        Next
        '  Update Grid with new table
        DataGrid1.DataSource = DTCloned

If you replace the names as necessary with those from your database, I'm pretty sure it will produce the result you wanted, even if we've drifted off the DataView approach

Let me know how it goes.

Ged

: This message was edited by kainsworth at 2004-10-11 14:41:3

---

: This message was edited by kainsworth at 2004-10-11 14:39:53

---

: Bill,
:
: I haven't succeeded yet in coming up with a fix that slots straight into your code as it stands. If it's any help, here's one way I came up with that allows you to analyze each row of a DataTable and if it finds a match in any column it adds that row to a new DataTable. Once it has gone through all the rows of the original table, the DataGrid is refreshed with the DataTable that now holds the search matches.
:
: In this example:
: DSOriginal is the DataSet holding the original data.
: I hope that the commenting explains enough as to how it works.
:

:   '  To start with, show original table in DataGrid
:         Dim DTOriginal As DataTable = DSOriginal.Tables(0)
:         DataGrid1.DataSource = DTOriginal
: 
:         '  Create new EMPTY DataTable by cloning structure of original
:         Dim DTCloned As DataTable = DTOriginal.Clone
: 
:         '  Import the matching DataRows into the cloned Table
:         Dim drtemp As DataRow
:         Dim j As Integer
:         ' Enumerate through all rows
:         For Each drtemp In DTOriginal.Rows
:             '  and within each row iterate through all columns
:             For j = 0 To DTOriginal.Columns.Count - 1
:                 '  If you find a match ..
:                 If drtemp.Item(j) = Me.txtSearch.Text Then
:                     '  add this row to the new DataTable
:                     DTCloned.ImportRow(drtemp)
:                     '  and stop looking along this row
:                     Exit For
:                 End If
:             Next
:         Next
:         '  Update Grid with new table
:         DataGrid1.DataSource = DTCloned

:
:
: If you replace the names as necessary with those from your database, I'm pretty sure it will produce the result you wanted, even if we've drifted off the DataView approach
:
: Let me know how it goes.
:
: Ged
:
:
:
:
:

: : This message was edited by kainsworth at 2004-10-11 14:41:3

---

: : This message was edited by kainsworth at 2004-10-11 14:39:53

---

: : Bill,
: :
: : I haven't succeeded yet in coming up with a fix that slots straight into your code as it stands. If it's any help, here's one way I came up with that allows you to analyze each row of a DataTable and if it finds a match in any column it adds that row to a new DataTable. Once it has gone through all the rows of the original table, the DataGrid is refreshed with the DataTable that now holds the search matches.
: :
: : In this example:
: : DSOriginal is the DataSet holding the original data.
: : I hope that the commenting explains enough as to how it works.
: :

: :   '  To start with, show original table in DataGrid
: :         Dim DTOriginal As DataTable = DSOriginal.Tables(0)
: :         DataGrid1.DataSource = DTOriginal
: : 
: :         '  Create new EMPTY DataTable by cloning structure of original
: :         Dim DTCloned As DataTable = DTOriginal.Clone
: : 
: :         '  Import the matching DataRows into the cloned Table
: :         Dim drtemp As DataRow
: :         Dim j As Integer
: :         ' Enumerate through all rows
: :         For Each drtemp In DTOriginal.Rows
: :             '  and within each row iterate through all columns
: :             For j = 0 To DTOriginal.Columns.Count - 1
: :                 '  If you find a match ..
: :                 If drtemp.Item(j) = Me.txtSearch.Text Then
: :                     '  add this row to the new DataTable
: :                     DTCloned.ImportRow(drtemp)
: :                     '  and stop looking along this row
: :                     Exit For
: :                 End If
: :             Next
: :         Next
: :         '  Update Grid with new table
: :         DataGrid1.DataSource = DTCloned

: :
: :
: : If you replace the names as necessary with those from your database, I'm pretty sure it will produce the result you wanted, even if we've drifted off the DataView approach
: :
: : Let me know how it goes.
: :
: : Ged
: :
: :
: : Here is what I have:
: : Dim DTOriginal As DataTable = ds1.Tables("gentest")
grdgentest.DataSource = DTOriginal
Dim DTCloned As DataTable = DTOriginal
Dim drtemp As DataRow
Dim j As Integer
For Each drtemp In DTOriginal.Rows
For j = 0 To DTOriginal.Columns.Count - 1
If drtemp.Item(j) = fs1.textbox1.Text Then
DTCloned.ImportRow(drtemp)
Exit For
End If
Next
Next
grdgentest.DataSource = DTCloned
I made a change in the first line as it kept giving me an error message. Here is what I had to do in the module also:
Friend f1 As DataForm1
Friend f2 As DataForm2
Friend fs2 As frmsearch2
Friend fs1 As frmsearch1
Friend dv As DataView
Friend ds1 As New DataSet
Friend grdgentest As New DataGrid
It now runs up until the For Each line and then gives the error message
"Object reference not set to an instance of an object". I think I need to add something more to the module. I also got that message on the first line until I Friended grdgentest as a new datagrid, that's why I think I need to add something there for the For Each line. Maybe I need to reference f1 in here somewhere ? I'm plugging away at it a piece at a time......but not quite there yet.
Bill
: :
:
:

I would think the key to your "missing object" problem is the often encountered one where you have declared a variable to hold your search form:

Dim fs1 as frmSearch1

but you haven't completed the instance of a frmSearch1 object (ie. instantiated it) with:

fs1 = New frmSearch1
' or of course, you could just use:
Dim fs1 as New frmSearch1

Pop that into the mixer and see if it throws out the result you want.

Ged

: I would think the key to your "missing object" problem is the often encountered one where you have declared a variable to hold your search form:
:

: Dim fs1 as frmSearch1
: 

: but you haven't completed the instance of a frmSearch1 object (ie. instantiated it) with:
:

: fs1 = New frmSearch1
: ' or of course, you could just use:
: Dim fs1 as New frmSearch1
: 

: Pop that into the mixer and see if it throws out the result you want.
:
: Ged
:
: I wish I could say that did it, but I'm still getting the same error message on the For Each line.
Bill
:
:
:
:
:

One little syntax I did notice in the code you posted was that you had:

          Dim DTCloned As DataTable = DTOriginal
'and not
  
        Dim DTCloned As DataTable = DTOriginal.Clone

ie. You left off the ".Clone" method.

I'm not saying that this is the cause of the Object Instance error - I think you'll get a different exception - but I do think you probably need to make the edit anyway.

Looking back over my (working) example and your (non-working) one, I start to wonder if the key to your problem is the DataTable named DTOriginal. One thing you ould try is to check that DTOriginal has been correctly created and populated. Something like:

  Debug.WriteLine(DTOriginal.Rows.Count)
        Debug.WriteLine(DTOriginal.Columns.Count)

would do this.
I'm not holding my breath that this will point us to the cause, but at least it will be one more thing we can eliminate.

Ged

: One little syntax I did notice in the code you posted was that you had:
:

:           Dim DTCloned As DataTable = DTOriginal
: 'and not
:   
:         Dim DTCloned As DataTable = DTOriginal.Clone
: 

: ie. You left off the ".Clone" method.
:
: I'm not saying that this is the cause of the Object Instance error - I think you'll get a different exception - but I do think you probably need to make the edit anyway.
:
: Looking back over my (working) example and your (non-working) one, I start to wonder if the key to your problem is the DataTable named DTOriginal. One thing you ould try is to check that DTOriginal has been correctly created and populated. Something like:
:

:   Debug.WriteLine(DTOriginal.Rows.Count)
:         Debug.WriteLine(DTOriginal.Columns.Count)
: 

: would do this.
: I'm not holding my breath that this will point us to the cause, but at least it will be one more thing we can eliminate.
:
: Ged
:
I feel bad that you have spent so much time on this...if it becomes a chore instead of a challenge, let me know.
Two things have happened.....before I put in the debug code it gave me the same error message on the line I missed Clone on.
Dim DTCloned as DataTable = DTOriginal.Clone
After that I plugged the Debug code in right after
Dim DTOriginal As DataTable = ds1.Tables("gentest")
and I get the same error message on the first line of Debug code
Object reference not set to an instance of an object, so I tend to agree with you that DTOriginal could very well be the culprit, or at least, what it is being Dim'ed as, unless I plugged the Debug code in the wrong place?
Bill

: I feel bad that you have spent so much time on this...if it becomes a chore instead of a challenge, let me know.
: Two things have happened.....before I put in the debug code it gave me the same error message on the line I missed Clone on.
: Dim DTCloned as DataTable = DTOriginal.Clone
: After that I plugged the Debug code in right after
: Dim DTOriginal As DataTable = ds1.Tables("gentest")
: and I get the same error message on the first line of Debug code
: Object reference not set to an instance of an object, so I tend to agree with you that DTOriginal could very well be the culprit, or at least, what it is being Dim'ed as, unless I plugged the Debug code in the wrong place?
: Bill
:
====================================================================

If your DataSet/Underlying database has only one Table in it, try this small edit and see if it gets you past the problem line:

'  Change this:
Dim DTOriginal As DataTable = ds1.Tables("gentest")
'   to this:
Dim DTOriginal As DataTable = ds1.Tables(0)

If your dataset/database has more than one table and "gentest" isn't the first table, then change the zero to the correct number to reflect the table's position in the DataSet.

: : I feel bad that you have spent so much time on this...if it becomes a chore instead of a challenge, let me know.
: : Two things have happened.....before I put in the debug code it gave me the same error message on the line I missed Clone on.
: : Dim DTCloned as DataTable = DTOriginal.Clone
: : After that I plugged the Debug code in right after
: : Dim DTOriginal As DataTable = ds1.Tables("gentest")
: : and I get the same error message on the first line of Debug code
: : Object reference not set to an instance of an object, so I tend to agree with you that DTOriginal could very well be the culprit, or at least, what it is being Dim'ed as, unless I plugged the Debug code in the wrong place?
: : Bill
: :
: ====================================================================
:
: If your DataSet/Underlying database has only one Table in it, try this small edit and see if it gets you past the problem line:
:

: 
: '  Change this:
: Dim DTOriginal As DataTable = ds1.Tables("gentest")
: '   to this:
: Dim DTOriginal As DataTable = ds1.Tables(0)
: 

: If your dataset/database has more than one table and "gentest" isn't the first table, then change the zero to the correct number to reflect the table's position in the DataSet.
:
:
: I tried the Tables(0) originally and that's when I changed it to the table name, it came up with "Cannot find table 0". gentest is the first table in the database of 3 tables. I also tried (I'm not sure why) changing it to 1 and 2, and it can't find them either. It doesn't give me an error when it is "gentest", the name of the first table in the database. I'm thinking of starting a whole new project just to see if maybe something got skewed along the way with all the changes. The project I'm currently using is one I made up just to get things working before I plugged it into my real project. I,m only using 1 dataset and datagrid per form/table.
Bill
:
:

: : : I feel bad that you have spent so much time on this...if it becomes a chore instead of a challenge, let me know.

Don't worry. It won't become a chore. Not promising it won't defeat me, but I like the challenge, so I'm game to keep going as long as you are.


#####################################################################

: : I tried the Tables(0) originally and that's when I changed it to the table name, it came up with "Cannot find table 0". gentest is the first table in the database of 3 tables. I also tried (I'm not sure why) changing it to 1 and 2, and it can't find them either. It doesn't give me an error when it is "gentest", the name of the first table in the database. I'm thinking of starting a whole new project just to see if maybe something got skewed along the way with all the changes. The project I'm currently using is one I made up just to get things working before I plugged it into my real project. I,m only using 1 dataset and datagrid per form/table.
: Bill

####################################################################
Can't imagine why it won't find a Table(0), I thought all DataSets had to have at least one Table, but I'm not enough of an ADO expert to know what the absence of Table(0) means.
If it was me, the next thing I'd do is swap out the Access database - I mean, use the current code (or one version of it) but change the connection, etc, details and pull data from a completely different database... obviously changing all the necessary parts of the original code. The object of the exercise to see if by some weird chance, it's the database or DataTable itself that's the root of the problem.
The theory being that the code as I posted it up to you works with a database of mine.

This is what Optimists call "Logical analysis of the problem" and what realists call "Clutching at straws" !

Ged

This message was edited by kainsworth at 2004-10-16 15:4:27

---

This message was edited by kainsworth at 2004-10-16 15:3:34

---

OK, I started afresh and I think that I might have nudged you off track along the way because I was using an XML file (and so had the easy route of the ReadXML method without all the clag of data connections, dataadapters, etc).
See if this code (amended as necessary to access your own database, table names, etc) will finally get you to the winning tape:

 Dim dbConnection As OleDbConnection
    Dim DA As OleDbDataAdapter
    Dim DS As DataSet

    Private Sub Form2_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load
      
        Try
            Dim connstr3 As String
            connstr3 = "Provider= Microsoft.Jet.OLEDB.4.0;Data Source=c:\Mydatabase.MDB"
            dbConnection = New OleDbConnection(connstr3)

            Dim strSQL As String = "SELECT * FROM [MainTopic]"

            Dim cmd As New OleDbCommand(strSQL, dbConnection)

            Dim DA As New OleDbDataAdapter
            DA.SelectCommand = cmd

            DS = New DataSet
            DA.Fill(DS)
        Catch ex As Exception
            MessageBox.Show(ex.ToString & "  while connecting to data.")
        End Try

        DataGrid1.DataSource = DS.Tables(0)

    End Sub

    
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        DataGrid1.DataSource = Nothing

        '  Create DataTable
        Dim DTOriginal As DataTable = DS.Tables(0)
        

        '  Create new DataTable by cloning structure of original
        Dim DTCloned As DataTable = DTOriginal.Clone

        '  Import the matching DataRows into the cloned Table
        Dim drtemp As DataRow
        Dim j As Integer
        ' Enumerate through all rows
        For Each drtemp In DTOriginal.Rows
            '  and within each row iterate through all columns
            For j = 0 To DTOriginal.Columns.Count - 1
                '  If you find a match ..
                If drtemp.Item(j).ToString = Trim(txtSearch.Text) Then
                    '  add this row to the new DataTable
                    DTCloned.ImportRow(drtemp)
                    '  and stop looking along this row
                    Exit For
                End If
            Next
        Next
        '  Update Grid with new table
        DataGrid1.DataSource = DTCloned
    End Sub

I took my own advice (as per my last post) and started afresh with a different Access database (which is how I came to discover that my code worked perfectly with XML, but threw the same errors as you when I used an MDB file)

Fingers crossed.

Ged

: This message was edited by kainsworth at 2004-10-16 15:4:27

---

: This message was edited by kainsworth at 2004-10-16 15:3:34

---

: OK, I started afresh and I think that I might have nudged you off track along the way because I was using an XML file (and so had the easy route of the ReadXML method without all the clag of data connections, dataadapters, etc).
: See if this code (amended as necessary to access your own database, table names, etc) will finally get you to the winning tape:
:

:  Dim dbConnection As OleDbConnection
:     Dim DA As OleDbDataAdapter
:     Dim DS As DataSet
: 
:     Private Sub Form2_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load
:       
:         Try
:             Dim connstr3 As String
:             connstr3 = "Provider= Microsoft.Jet.OLEDB.4.0;Data Source=c:\Mydatabase.MDB"
:             dbConnection = New OleDbConnection(connstr3)
: 
:             Dim strSQL As String = "SELECT * FROM [MainTopic]"
: 
:             Dim cmd As New OleDbCommand(strSQL, dbConnection)
: 
:             Dim DA As New OleDbDataAdapter
:             DA.SelectCommand = cmd
: 
:             DS = New DataSet
:             DA.Fill(DS)
:         Catch ex As Exception
:             MessageBox.Show(ex.ToString & "  while connecting to data.")
:         End Try
: 
:         DataGrid1.DataSource = DS.Tables(0)
: 
:     End Sub
: 
:     
:     Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
:         DataGrid1.DataSource = Nothing
: 
:         '  Create DataTable
:         Dim DTOriginal As DataTable = DS.Tables(0)
:         
: 
:         '  Create new DataTable by cloning structure of original
:         Dim DTCloned As DataTable = DTOriginal.Clone
: 
:         '  Import the matching DataRows into the cloned Table
:         Dim drtemp As DataRow
:         Dim j As Integer
:         ' Enumerate through all rows
:         For Each drtemp In DTOriginal.Rows
:             '  and within each row iterate through all columns
:             For j = 0 To DTOriginal.Columns.Count - 1
:                 '  If you find a match ..
:                 If drtemp.Item(j).ToString = Trim(txtSearch.Text) Then
:                     '  add this row to the new DataTable
:                     DTCloned.ImportRow(drtemp)
:                     '  and stop looking along this row
:                     Exit For
:                 End If
:             Next
:         Next
:         '  Update Grid with new table
:         DataGrid1.DataSource = DTCloned
:     End Sub
: 

:
: I took my own advice (as per my last post) and started afresh with a different Access database (which is how I came to discover that my code worked perfectly with XML, but threw the same errors as you when I used an MDB file)
:
: Fingers crossed.
:
: Ged
:
:OK....let me try this.......I'll let you know. I did make a zip file of my test project that I can send you if need be.
Bill
:
:
:

: : This message was edited by kainsworth at 2004-10-16 15:4:27

---

: : This message was edited by kainsworth at 2004-10-16 15:3:34

---

: : OK, I started afresh and I think that I might have nudged you off track along the way because I was using an XML file (and so had the easy route of the ReadXML method without all the clag of data connections, dataadapters, etc).
: : See if this code (amended as necessary to access your own database, table names, etc) will finally get you to the winning tape:
: :

: :  Dim dbConnection As OleDbConnection
: :     Dim DA As OleDbDataAdapter
: :     Dim DS As DataSet
: : 
: :     Private Sub Form2_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load
: :       
: :         Try
: :             Dim connstr3 As String
: :             connstr3 = "Provider= Microsoft.Jet.OLEDB.4.0;Data Source=c:\Mydatabase.MDB"
: :             dbConnection = New OleDbConnection(connstr3)
: : 
: :             Dim strSQL As String = "SELECT * FROM [MainTopic]"
: : 
: :             Dim cmd As New OleDbCommand(strSQL, dbConnection)
: : 
: :             Dim DA As New OleDbDataAdapter
: :             DA.SelectCommand = cmd
: : 
: :             DS = New DataSet
: :             DA.Fill(DS)
: :         Catch ex As Exception
: :             MessageBox.Show(ex.ToString & "  while connecting to data.")
: :         End Try
: : 
: :         DataGrid1.DataSource = DS.Tables(0)
: : 
: :     End Sub
: : 
: :     
: :     Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
: :         DataGrid1.DataSource = Nothing
: : 
: :         '  Create DataTable
: :         Dim DTOriginal As DataTable = DS.Tables(0)
: :         
: : 
: :         '  Create new DataTable by cloning structure of original
: :         Dim DTCloned As DataTable = DTOriginal.Clone
: : 
: :         '  Import the matching DataRows into the cloned Table
: :         Dim drtemp As DataRow
: :         Dim j As Integer
: :         ' Enumerate through all rows
: :         For Each drtemp In DTOriginal.Rows
: :             '  and within each row iterate through all columns
: :             For j = 0 To DTOriginal.Columns.Count - 1
: :                 '  If you find a match ..
: :                 If drtemp.Item(j).ToString = Trim(txtSearch.Text) Then
: :                     '  add this row to the new DataTable
: :                     DTCloned.ImportRow(drtemp)
: :                     '  and stop looking along this row
: :                     Exit For
: :                 End If
: :             Next
: :         Next
: :         '  Update Grid with new table
: :         DataGrid1.DataSource = DTCloned
: :     End Sub
: : 

: :
: : I took my own advice (as per my last post) and started afresh with a different Access database (which is how I came to discover that my code worked perfectly with XML, but threw the same errors as you when I used an MDB file)
: :
: : Fingers crossed.
: :
: : Ged
: :
: :OK....let me try this.......I'll let you know. I did make a zip file of my test project that I can send you if need be.
: Bill
: :
: :I think I'm beginning to see the problem. I used the DataForm wizard to make my form with the datagrid on it. The wizard puts the OleDbConnection, OleDbDataAdapter, and DataSet objects on the form automatically with all the code to create the Load, Fill, Update, Delete, Insert, and Select commands with a Load button and Update button. I put the load code in the Form Load event so that the datagrid would be filled automatically upon execution. It looks to me as if you are making the database connection and filling the datagrid through code instead of the DataAdapter. I think there is a conflict between the way the two are executed and the way they are referred to in each one's code. I assume the form you are calling Form2 is the form with the datagrid. What form are you using and how are you getting the OleDbConnection, OleDbDataAdapter, and DataSet objects on the form ? Am I on the right track here ? I'm also thinking it matters whether to use a "Typed" or "Untyped" DataSet. Probably "Untyped". I'm going to try substituting your code for the Wizards code in the form load event and see if that works, otherwise I'm going to start a new project without using the Wizard and see if that works.
Bill
: :
:
:

This message was edited by Bill H at 2004-10-16 18:38:39

---

: : : This message was edited by kainsworth at 2004-10-16 15:4:27

---

: : : This message was edited by kainsworth at 2004-10-16 15:3:34

---

: : : OK, I started afresh and I think that I might have nudged you off track along the way because I was using an XML file (and so had the easy route of the ReadXML method without all the clag of data connections, dataadapters, etc).
: : : See if this code (amended as necessary to access your own database, table names, etc) will finally get you to the winning tape:
: : :

: : :  Dim dbConnection As OleDbConnection
: : :     Dim DA As OleDbDataAdapter
: : :     Dim DS As DataSet
: : : 
: : :     Private Sub Form2_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load
: : :       
: : :         Try
: : :             Dim connstr3 As String
: : :             connstr3 = "Provider= Microsoft.Jet.OLEDB.4.0;Data Source=c:\Mydatabase.MDB"
: : :             dbConnection = New OleDbConnection(connstr3)
: : : 
: : :             Dim strSQL As String = "SELECT * FROM [MainTopic]"
: : : 
: : :             Dim cmd As New OleDbCommand(strSQL, dbConnection)
: : : 
: : :             Dim DA As New OleDbDataAdapter
: : :             DA.SelectCommand = cmd
: : : 
: : :             DS = New DataSet
: : :             DA.Fill(DS)
: : :         Catch ex As Exception
: : :             MessageBox.Show(ex.ToString & "  while connecting to data.")
: : :         End Try
: : : 
: : :         DataGrid1.DataSource = DS.Tables(0)
: : : 
: : :     End Sub
: : : 
: : :     
: : :     Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
: : :         DataGrid1.DataSource = Nothing
: : : 
: : :         '  Create DataTable
: : :         Dim DTOriginal As DataTable = DS.Tables(0)
: : :         
: : : 
: : :         '  Create new DataTable by cloning structure of original
: : :         Dim DTCloned As DataTable = DTOriginal.Clone
: : : 
: : :         '  Import the matching DataRows into the cloned Table
: : :         Dim drtemp As DataRow
: : :         Dim j As Integer
: : :         ' Enumerate through all rows
: : :         For Each drtemp In DTOriginal.Rows
: : :             '  and within each row iterate through all columns
: : :             For j = 0 To DTOriginal.Columns.Count - 1
: : :                 '  If you find a match ..
: : :                 If drtemp.Item(j).ToString = Trim(txtSearch.Text) Then
: : :                     '  add this row to the new DataTable
: : :                     DTCloned.ImportRow(drtemp)
: : :                     '  and stop looking along this row
: : :                     Exit For
: : :                 End If
: : :             Next
: : :         Next
: : :         '  Update Grid with new table
: : :         DataGrid1.DataSource = DTCloned
: : :     End Sub
: : : 

: : :
: : : I took my own advice (as per my last post) and started afresh with a different Access database (which is how I came to discover that my code worked perfectly with XML, but threw the same errors as you when I used an MDB file)
: : :
: : : Fingers crossed.
: : :
: : : Ged
: : :
: : :OK....let me try this.......I'll let you know. I did make a zip file of my test project that I can send you if need be.
: : Bill
: : :
: : :I think I'm beginning to see the problem. I used the DataForm wizard to make my form with the datagrid on it. The wizard puts the OleDbConnection, OleDbDataAdapter, and DataSet objects on the form automatically with all the code to create the Load, Fill, Update, Delete, Insert, and Select commands with a Load button and Update button. I put the load code in the Form Load event so that the datagrid would be filled automatically upon execution. It looks to me as if you are making the database connection and filling the datagrid through code instead of the DataAdapter. I think there is a conflict between the way the two are executed and the way they are referred to in each one's code. I assume the form you are calling Form2 is the form with the datagrid. What form are you using and how are you getting the OleDbConnection, OleDbDataAdapter, and DataSet objects on the form ? Am I on the right track here ? I'm also thinking it matters whether to use a "Typed" or "Untyped" DataSet. Probably "Untyped". I'm going to try substituting your code for the Wizards code in the form load event and see if that works, otherwise I'm going to start a new project without using the Wizard and see if that works.
: Bill
: : :
: :
: :
: I seem to be getting nowhere fast.....I tried making an entire new project and still getting errors......it has to be me, I'm doing something wrong. I'm going to send you my test project that I have been using since you first started helping me. I hope I did that right because I've not used WinZip before. I couldn't get it to zip the bin and obj files in folders, they are mixed in so I hope it doesn't matter. I don't see any place to attach a file so please let me know how to get it to you.
Bill
:

Bill,
I've sent details to your MailBox of the best email address to use to send me your project.

By coincidence, this morning I decided I was going to create an MDB file along the lines of the one you've described in your various posts, but I'll wait now and use the genuine article instead

Re Data Wizards, when I first began with VB.Net I used the data objects from the toolbox, but once I learned how to create them in code I never went back to the Data tab in the toolbox. I'm not knocking it though - It's a tremendously useful facility provided by the Visual Studio team, a great stepping stone for beginners in ADO.Net projects.

I just somehow feel I have more control if I can see the code typed there on my form. It's a personal choice thing.

Look forward to having a tinker with the project when it arrives .

Ged

===================================================================



===============================================================

: : : :I think I'm beginning to see the problem. I used the DataForm wizard to make my form with the datagrid on it. The wizard puts the OleDbConnection, OleDbDataAdapter, and DataSet objects on the form automatically with all the code to create the Load, Fill, Update, Delete, Insert, and Select commands with a Load button and Update button. I put the load code in the Form Load event so that the datagrid would be filled automatically upon execution. It looks to me as if you are making the database connection and filling the datagrid through code instead of the DataAdapter. I think there is a conflict between the way the two are executed and the way they are referred to in each one's code. I assume the form you are calling Form2 is the form with the datagrid. What form are you using and how are you getting the OleDbConnection, OleDbDataAdapter, and DataSet objects on the form ? Am I on the right track here ? I'm also thinking it matters whether to use a "Typed" or "Untyped" DataSet. Probably "Untyped". I'm going to try substituting your code for the Wizards code in the form load event and see if that works, otherwise I'm going to start a new project without using the Wizard and see if that works.
: : Bill
: : : :
: : :
: : :
: : I seem to be getting nowhere fast.....I tried making an entire new project and still getting errors......it has to be me, I'm doing something wrong. I'm going to send you my test project that I have been using since you first started helping me. I hope I did that right because I've not used WinZip before. I couldn't get it to zip the bin and obj files in folders, they are mixed in so I hope it doesn't matter. I don't see any place to attach a file so please let me know how to get it to you.
: Bill
: :
:
:
:
: