DataGrid update issues

13 Feb 2006 5:54 AM

BStrick

I've looked around and haven't found a usuable solution to this issue.
I hope that you can provide me with some assistance. I have a
application that calls for the user to select a database/table to view
data from. At that point a datagrid populates with the information.
This works fine except when the user tries to either repopulate that
grid with the same table or with data from a different table.

If the user tries to repopluate from the same table then if should
simply overwrite what was there at first. If they try to populate from
a diffferent table then it should erase the old data and input the new.

Instead what I get when i try to repopulate with the same table is that
it inputs additional data starting at the last row from the frst
attempt. If I am populating the grid from a new table then it will keep
all the previous columns and add the new data to the last column on the
left from the first attemp.

Here is my code

Dim objIntConn As New OleDbConnection
Dim objIntDataset As New DataSet
Dim objIntDataset As New DataSet

Private Sub Populate()
Try
                objIntConn.Open()

                objIntAdapter.SelectCommand = New OleDbCommand
                objIntAdapter.SelectCommand.Connection = objIntConn
                objIntAdapter.SelectCommand.CommandType =
CommandType.TableDirect
                objIntAdapter.SelectCommand.CommandText =
cmbIntTbl.Text

                Try
                    'objIntDataset.Reset()
                    'objIntDataset.Tables("IntTable").Clear()
                    'objIntDataset.Tables.add("IntTable")
                    'dgIntData.DataBindings.Clear()
                Catch
                End Try

                objIntAdapter.Fill(objIntDataset, "IntTable")

                objIntConn.Close()

                dgIntData.DataSource = objIntDataset
                dgIntData.DataMember = "IntTable"
                dgIntData.AutoGenerateColumns = True
                dgIntData.AutoResizeColumns()
            Catch
                MessageBox.Show("An error occured while processing
data", "Error", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
            Finally
                objIntConn.Close()
            End Try

You can see that I've tried a couple of different solutions and none of
them have worked.

Please Help!!

13 Feb 2006 8:40 AM

Cor Ligthert [MVP]

BStrick,

Did you try this already

objIntDataset.Tables("IntTable").Clear()
objIntAdapter.Fill(objIntDataset, "IntTable")

I am not sure if this is working, I use this forever with

dgIntData.DataSource = objIntDataset.Tables("IntTable")

By the way, why are you setting so consequent obj before everything, I see
this seldom done and nowhere in the documentation from Microsoft. In Net
everything is an object even your dg.

Another point is the Open and Close of the connection. The dataadapter does
that for you. (If you be consequent and not do an open before it), so just
removing it makes your code cleaner.

I hope this helps,

Cor

13 Feb 2006 1:48 PM

BStrick

I will try the objIntDataSet.Tables("IntTable").Clear method again when
I get home, but if I recall, it was causing my datagrid to return blank
when I tried to use it. I will also remove the .open and .close
methods. Its just a force of habit from VB.6.0 I guess.

Thank You
I'll let you know if this works

14 Feb 2006 12:28 AM

BStrick

I don't know whats going on... it did'nt wrk. Does anyone else have any
ideas? I did a test to see where the error is coming from and believe
it is either with the dataAdapter or the dataset. I've tried to use the
Clear and Reset methods for both of them and didn't get any desired
results. I'm lost.

14 Feb 2006 4:05 AM

Otis Mukinfus

On 12 Feb 2006 21:54:09 -0800, "BStrick"
<bstrickl***@strictlyconsulting.net> wrote:

Show quote

>I've looked around and haven't found a usuable solution to this issue.
>I hope that you can provide me with some assistance. I have a
>application that calls for the user to select a database/table to view
>data from. At that point a datagrid populates with the information.
>This works fine except when the user tries to either repopulate that
>grid with the same table or with data from a different table.
>
>If the user tries to repopluate from the same table then if should
>simply overwrite what was there at first. If they try to populate from
>a diffferent table then it should erase the old data and input the new.
>
>Instead what I get when i try to repopulate with the same table is that
>it inputs additional data starting at the last row from the frst
>attempt. If I am populating the grid from a new table then it will keep
>all the previous columns and add the new data to the last column on the
>left from the first attemp.
>
>Here is my code
>
>Dim objIntConn As New OleDbConnection
>Dim objIntDataset As New DataSet
>Dim objIntDataset As New DataSet
>
>Private Sub Populate()
>Try
>                objIntConn.Open()
>
>                objIntAdapter.SelectCommand = New OleDbCommand
>                objIntAdapter.SelectCommand.Connection = objIntConn
>                objIntAdapter.SelectCommand.CommandType =
>CommandType.TableDirect
>                objIntAdapter.SelectCommand.CommandText =
>cmbIntTbl.Text
>
>
>                Try
>                    'objIntDataset.Reset()
>                    'objIntDataset.Tables("IntTable").Clear()
>                    'objIntDataset.Tables.add("IntTable")
>                    'dgIntData.DataBindings.Clear()
>                Catch
>                End Try
>
>                objIntAdapter.Fill(objIntDataset, "IntTable")
>
>                objIntConn.Close()
>
>                dgIntData.DataSource = objIntDataset
>                dgIntData.DataMember = "IntTable"
>                dgIntData.AutoGenerateColumns = True
>                dgIntData.AutoResizeColumns()
>            Catch
>                MessageBox.Show("An error occured while processing
>data", "Error", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
>            Finally
>                objIntConn.Close()
>            End Try
>
>You can see that I've tried a couple of different solutions and none of
>them have worked.
>
>
>Please Help!!

To clear a grid and add new data without appending it in C# you would
simply code: YourGrid.DataSource = null;

Then refill it from the DataDataSet.

Otis Mukinfus
http://www.otismukinfus.com
http://www.tomchilders.com