Datagridview doesn't update current row values

[Phil]

VB2008
I have a DataGridView with MultiSelect = True and
SelectionMode=F ullRowSelect. One of the columns is a checkbox column. I have
a function that goes through all the selected rows and sets the value of
this column.

For Each row In DataGridView1.S electedRows
row.Cells("MyCh eckboxColumn"). Value = False
Next

This seems to almost work, but I noticed that sometimes it does not update
the first or the last selected row. On investigation, it seems that the
value is updated, but if the row happens to be the currentrow, the change is
not displayed until the currentrow is changed. I have managed to get around
this problem by setting CurrentCell = Nothing after I have made the changes,
but this has the undesirable side effect of clearing the selection.

Any suggestions?

TIA
Phil.

[Linda Liu[MSFT]]

Hi Phil,

I performed a test based on your description but didn't reproduce the
problem on my side. All selected rows in the DataGridView are updated
immediately in my test application.

I create a WinForm Application project in VS2008 and add a DataGridView and
a Button on the Form1. I add a DataGridViewChe ckBoxColumn in the
DataGridView. The following is the code in the Form1.vb:

Public Class Form1
Private Sub Form1_Load(ByVa l sender As System.Object, ByVal e As
System.EventArg s) Handles MyBase.Load
Me.DataGridView 1.SelectionMode =
DataGridViewSel ectionMode.Full RowSelect
Me.DataGridView 1.RowCount = 10
For i As Integer = 0 To 9
Me.DataGridView 1.Rows(i).Cells (0).Value = True
Next
End Sub

Private Sub Button1_Click(B yVal sender As System.Object, ByVal e As
System.EventArg s) Handles Button1.Click
For Each row As DataGridViewRow In Me.DataGridView 1.SelectedRows
row.Cells(0).Va lue = False
Next
End Sub
End Class

Build and run the application. Select some rows in the DataGridView with
Mouse and click the Button, all selected rows are updated immediately.
Is there any difference between your code and mine?

Sincerely,
Linda Liu
Microsoft Online Community Support

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[Phil]

"Linda Liu[MSFT]" <v-****@online.mic rosoft.comwrote in message
news:Fj******** ******@TK2MSFTN GHUB02.phx.gbl. ..

Hi Phil,

I performed a test based on your description but didn't reproduce the
problem on my side. All selected rows in the DataGridView are updated
immediately in my test application.

Thanks for looking at this. My datagridview is part of a larger application,
so there is quite a lot of difference from your code. I shall try to
reproduce the problem in a smaller app. The main thing that springs to mind
that is different is that my data is populated from a datasource (OleDb -
access/jet). I'm not sure if that is relevant.

Phil.

[Phil]

"Linda Liu[MSFT]" <v-****@online.mic rosoft.comwrote in message
news:Fj******** ******@TK2MSFTN GHUB02.phx.gbl. ..

Hi Phil,

I performed a test based on your description but didn't reproduce the
problem on my side. All selected rows in the DataGridView are updated
immediately in my test application.

OK. I have managed to adapt your code to reproduce the problem.
Create the datagridview initially with no columns and replace Form_Load
as follows:

Private Sub Form1_Load(ByVa l sender As System.Object, ByVal e As
System.EventArg s) Handles MyBase.Load

Me.DataGridView 1.SelectionMode = DataGridViewSel ectionMode.Full RowSelect

Dim data As New DataTable
data.Columns.Ad d("Column1", Type.GetType("S ystem.Int16"))
For i As Integer = 0 To 9
data.Rows.Add(1 )
Next

Me.DataGridView 1.DataSource = data

Dim col As New DataGridViewChe ckBoxColumn
Me.DataGridView 1.Columns.Add(c ol)
col.DataPropert yName = "Column1"

End Sub

[Phil]

OK. I have managed to adapt your code to reproduce the problem.

Create the datagridview initially with no columns and replace Form_Load
as follows:

Private Sub Form1_Load(ByVa l sender As System.Object, ByVal e As
System.EventArg s) Handles MyBase.Load

Me.DataGridView 1.SelectionMode =
DataGridViewSel ectionMode.Full RowSelect

Dim data As New DataTable
data.Columns.Ad d("Column1", Type.GetType("S ystem.Int16"))
For i As Integer = 0 To 9
data.Rows.Add(1 )
Next

Me.DataGridView 1.DataSource = data

Dim col As New DataGridViewChe ckBoxColumn
Me.DataGridView 1.Columns.Add(c ol)
col.DataPropert yName = "Column1"

End Sub

It seems the problem occurs when there are two columns bound to the same
data property.
If I add:
Me.DataGridView 1.Columns.Remov e("Column1")
The problem does not occur.

In my main application I hide this column. I shall try removing it instead,
and see if that fixes it.
It does seem to be a bug in the datagridview data binding though.

[Phil]

In my main application I hide this column. I shall try removing it
instead,
and see if that fixes it.

It didn't fix it :-(
Not sure why, perhaps because there are other columns too.

[Phil]

It seems the problem occurs when there are two columns bound to the same
data property.

The reason I am doing this, is because the column does not automatically
appear as a checkbox. The underlying SQL query is of the following form:

SELECT EXISTS(subquery ), ....

For some reason the result of the EXISTS function seems to come back as an
integer in the Dataset. If there was some way to make this return a boolean,
that might solve my problem. This is OleDb (access/jet).

[Linda Liu[MSFT]]

Hi Phil,

Thank you for your prompt reply!

I performed a test based on your sample code and did reproduce the problem
on my side. If I update the data in the data source in code directly, the
problem also exists even if there's only one DataGridViewChe ckBoxColumn in
the DataGridView.

This problem is not relevant to multiple columns' being bound to the same
data property.

The reason behind this problem is that data binding doesn't refresh data of
the current item in UI when the data in the underlying data source are
changed.

The workaround is to call the EndCurrentEdit method of the corresponding
BindingManagerB ase object associated with the data source to end current
edit to the data source and refresh the UI.

For example, after you change the value of the DataGridViewCel ls or change
the data in the data source directly, add the following line of code:
Me.BindingConte xt(data).EndCur rentEdit()

For some reason the result of the EXISTS function seems to come back as

an integer in the Dataset.

The EXISTS operator returns a value of bit. In .NET, the corresponding type
is Boolean. If a data column is of type Boolean, DataGridView will generate
a DataGridViewChe ckBoxColumn for this data column.

Is the DataTable strong-typed in your application? If so, you may open the
DataSet in the designer and select the column of the DataTable and check
the column's type in the Properties window. If not, you need to set a break
point in your code and press F5 to run the application. When the
application enters into break mode, you can check the type of the
DataTable's column.

Hope this helps.
If you have any question, please feel free to let me know.

Sincerely,
Linda Liu
Microsoft Online Community Support

Delighting our customers is our #1 priority. We welcome your comments and
suggestions about how we can improve the support we provide to you. Please
feel free to let my manager know what you think of the level of service
provided. You can send feedback directly to my manager at:
ms****@microsof t.com.

This posting is provided "AS IS" with no warranties, and confers no rights.

[Linda Liu[MSFT]]

Hi Phil,

How about the problem now?

If you have any question, please feel free to let me know.

Thank you for using our MSDN Managed Newsgroup Support Service!

Sincerely,
Linda Liu
Microsoft Online Community Support

Delighting our customers is our #1 priority. We welcome your comments and
suggestions about how we can improve the support we provide to you. Please
feel free to let my manager know what you think of the level of service
provided. You can send feedback directly to my manager at:
ms****@microsof t.com.

This posting is provided "AS IS" with no warranties, and confers no rights.

[Phil]

I performed a test based on your sample code and did reproduce the problem

on my side. If I update the data in the data source in code directly, the
problem also exists even if there's only one DataGridViewChe ckBoxColumn in
the DataGridView.

OK.

>
This problem is not relevant to multiple columns' being bound to the same
data property.

OK. That was just a theory :-)

>
The reason behind this problem is that data binding doesn't refresh data
of
the current item in UI when the data in the underlying data source are
changed.

OK. That makes sense I think. It still thinks the row is being edited, so
doesn't refresh until the current row is changed.

>
The workaround is to call the EndCurrentEdit method of the corresponding
BindingManagerB ase object associated with the data source to end current
edit to the data source and refresh the UI.

OK.

>
For example, after you change the value of the DataGridViewCel ls or change
the data in the data source directly, add the following line of code:
Me.BindingConte xt(data).EndCur rentEdit()

I'll try that. Thanks.

>

>For some reason the result of the EXISTS function seems to come back as

an integer in the Dataset.

The EXISTS operator returns a value of bit. In .NET, the corresponding
type
is Boolean. If a data column is of type Boolean, DataGridView will
generate
a DataGridViewChe ckBoxColumn for this data column.

Is the DataTable strong-typed in your application?

No.

If so, you may open the
DataSet in the designer and select the column of the DataTable and check
the column's type in the Properties window. If not, you need to set a
break
point in your code and press F5 to run the application. When the
application enters into break mode, you can check the type of the
DataTable's column.

I think I have done this, and IIRC it was returning Int16. I'll check this
again tomorrow.

>

Thanks for your help.
Phil.