We help IT Professionals succeed at work.

vb.net dataadapter update and datagridview

jackjohnson44
on
Medium Priority
1,192 Views
Last Modified: 2008-01-09
I am populating a datagridview with a db, then I type in a new row, then try to update.
How do I get this to work?

   This does not work:

    Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
        dataAdapter.Update(myDataSet)
    End Sub

   This fills my datagrid:

    Private Sub refreshDataGRid()

        dataAdapter.SelectCommand = New OleDbCommand("select * from users", myConnection)

        Dim CB As OleDbCommandBuilder
        CB = New OleDbCommandBuilder(dataAdapter)

        dataAdapter.UpdateCommand = CB.GetUpdateCommand()

        dataAdapter.Fill(myDataSet)

        myDataSet = getDataSet("select * from users")
        myDataSet.Tables(0).TableName = "users"
        myDataTable = myDataSet.Tables("users")
        DataGridView1.DataSource = myDataTable

        DataGridView1.Columns("userName").HeaderText = "User Name"
        DataGridView1.Columns("pass").HeaderText = "Password"

        If Not DataGridView1.Columns.Contains("Delete") Then
            Dim buttons As New DataGridViewButtonColumn()
            With buttons
                .HeaderText = "Delete"
                .Text = "Delete"
                .Name = "Delete"
                .UseColumnTextForButtonValue = True
                .AutoSizeMode = DataGridViewAutoSizeColumnMode.DisplayedCells
                .FlatStyle = FlatStyle.Standard
                .DisplayIndex = 0
            End With

            DataGridView1.Columns.Add(buttons)
        End If

    End Sub
Comment
Watch Question

1) there is no need for this line
dataAdapter.UpdateCommand = CB.GetUpdateCommand()
since you already set the CommandBuilder to the dataadapter it will be set automatically

2) there is no need for
dataAdapter.Fill(myDataSet)
myDataSet = getDataSet("select * from users")
        myDataSet.Tables(0).TableName = "users"
        myDataTable = myDataSet.Tables("users")
either.

replace that with

dim MyDataTable as New DataTable("users")
myDataSet.Tables.Add(MyDataTable )
dataAdapter.Fill(MyDataTable )
DataGridView1.DataSource = MyDataTable

directly


how about now, does this work with these changes? hope it helps somehting
NY

Commented:
Use
myDataSet .AcceptChanges()
'after calling the adapter update command for commiting it

Try It
manch, the dataadapter by default calls acceptchanges on update, unless he changed it manually there's no need to do that.

Author

Commented:
newyuppie, can you please explain what you are doing?

1.  are you creating a new table with nothing in it, and the dataadapter knows how to fill it?

2. What is wrong with the way that I did it?  Can you please explain why this is wrong?

3. I am not sure what is going on, but I tried to do this, type something into the grid, then call dataAdapter.Update(myDataSet) and it does not fail.  Then I close the app, reopen it and fill the grid and it does not have the new row.  Do I have to have an insert id?  I tried leaving it blank and also filling in the next number and nothing happened.

Author

Commented:
here is what I have so far
<?xml version="1.0" standalone="yes"?>
<NewDataSet>
  <users>
    <ID>52</ID>
    <userName>admin</userName>
    <pass>admin</pass>
    <level>3</level>
    <active>true</active>
  </users>
  <users>
    <ID>55</ID>
    <userName>test</userName>
    <pass>test</pass>
    <level>1</level>
    <active>true</active>
  </users>
</NewDataSet>

    Private Sub refreshDataGRid()

        dataAdapter.SelectCommand = New OleDbCommand("select * from users", myConnection)

        Dim CB As OleDbCommandBuilder
        CB = New OleDbCommandBuilder(dataAdapter)

        dataAdapter.UpdateCommand = CB.GetUpdateCommand()

        dataAdapter.Fill(myDataSet)

        'myDataSet = getDataSet("select * from users")
        'myDataSet.Tables(0).TableName = "users"
        'myDataTable = myDataSet.Tables("users")
        'DataGridView1.DataSource = myDataTable

        myDataTable = New DataTable("users")
        myDataSet.Tables.Add(MyDataTable)
        dataAdapter.Fill(MyDataTable)
        DataGridView1.DataSource = MyDataTable



        DataGridView1.Columns("userName").HeaderText = "User Name"
        DataGridView1.Columns("pass").HeaderText = "Password"
end sub

this does nothing, (I have tried all of these, also leaving them out, and different combinations)
        DataGridView1.Update()
        myDataSet.AcceptChanges()
        dataAdapter.Update(myDataSet)
this is what you should have:

Private Sub refreshDataGRid()

        dataAdapter.SelectCommand = New OleDbCommand("select * from users", myConnection)

        Dim CB As OleDbCommandBuilder
        CB = New OleDbCommandBuilder(dataAdapter)

        myDataTable = New DataTable("users")
        myDataSet.Tables.Add(MyDataTable)
        dataAdapter.Fill(MyDataTable)
        DataGridView1.DataSource = MyDataTable

        DataGridView1.Columns("userName").HeaderText = "User Name"
        DataGridView1.Columns("pass").HeaderText = "Password"
end sub

private sub ButtonSave_Click(sender as object, e as eventargs) handles ButtonSave.Click
dataAdapter.Update(MyDataSet)
End SUb


you will need to add a button called ButtonSave, so that it will save when you press it.
CERTIFIED EXPERT
Most Valuable Expert 2012
Top Expert 2008

Commented:
You need to be very careful when calling AcceptChanges, or it will change the row status of the rows to Unmodified, and nothing will happen if you call it before OleDbDataAdapter.Update.

Bob

Author

Commented:
newyuppie, that did not work.
I am getting this error: "Update unable to find TableMapping['Table'] or DataTable 'Table'."

Is the problem that you are binding the datagridview to a table, and then trying to update the dataset?
   DataGridView1.DataSource = MyDataTable
   dataAdapter.Update(MyDataSet)

Should they both be set to datasets?
CERTIFIED EXPERT
Most Valuable Expert 2012
Top Expert 2008

Commented:
If you call the Fill method, and don't specify a table alias, it will be called Table1:

dataAdapter.Fill(MyDataSet, "Table")

  and

dataAdapter.Update(MyDataSet, "Table")

If you only have 1 DataTable in the DataSet, then it is more efficient to fill a DataTable, then have an entire DataSet.

Bob

Author

Commented:
Thanks, but I am not sure what you are saying.

In the example from newyuppie, it says fill the dataadapter with a table , the fill the DataGridView1.DataSource with the datatable.
You are saying fill it with a dataset.

Which one do I use?

Your answer does not work with the function refreshDataGRid in the example from newyuppie.

Also, can you show me what you mean by using the name of my table "users" instead of "Table".

Can you either show me how to make refreshDataGRid work with dataAdapter.Update(MyDataSet, "Table"), or show me how to make the update line work with that function?

CERTIFIED EXPERT
Most Valuable Expert 2012
Top Expert 2008

Commented:
This is what I am saying:

1) Add an alias with a DataSet:

      Dim ds As New DataSet
      dataAdapter.Fill(ds, "users" )

2) Create a DataTable

    Dim dt As New DataTable
    dataAdapter.Fill(dt)

If you only have one table, then I feel that it is best to use the DataTable approach, since it has less overhead and is more efficient on processor and memory usage.

Bob

Author

Commented:
Thanks for your help, but I am still completely confused.
I am new to datasets and can't figure it out.
I think there are some steps missing since plugging in either of these 2 line chunks won't even fill the datagridview.

1.  How would you get either #1, or #2 to fill a datagridview?  Again I am working with the function above.

2. After that function is working with method #1, or method #2, how is the update called?

I am no closer to a solution than when I first started.

Since there isn't much to change, can you please re-write the function above, and show me the update line?

I would think it would be changing one or two lines.
CERTIFIED EXPERT
Most Valuable Expert 2012
Top Expert 2008

Commented:
1) Try this:

Private Sub refreshDataGRid()

   Dim dataAdapter As New OleDbDataAdapter("Select * From Users", myConnectionString)
 
   Dim CB As OleDbCommandBuilder As New OleDbCommandBuilder(dataAdapter)
   dataAdapter.UpdateCommand = CB.GetUpdateCommand()

   Dim myTable As New DataTable
   dataAdapter.Fill(myTable)

   DataGridView1.AutoGenerateColumns = False

   DataGridView1.DataSource = myTable

End Sub

2) If you are defining the columns through the property designer, then define this there, instead of in code:

    DataGridView1.Columns("userName").HeaderText = "User Name"
    DataGridView1.Columns("pass").HeaderText = "Password"

3) Also, if you are defining the columns, add the <Delete> button column there also.

Bob

Author

Commented:
This function does not work.  My grid is blank.

Private Sub refreshDataGRid()

   Dim dataAdapter As New OleDbDataAdapter("Select * From Users", myConnectionString)
 
   Dim CB As OleDbCommandBuilder As New OleDbCommandBuilder(dataAdapter)
   dataAdapter.UpdateCommand = CB.GetUpdateCommand()

   Dim myTable As New DataTable
   dataAdapter.Fill(myTable)

   DataGridView1.AutoGenerateColumns = False

   DataGridView1.DataSource = myTable

End Sub
CERTIFIED EXPERT
Most Valuable Expert 2012
Top Expert 2008
Commented:
Is myTable.Rows.Count > 0?

Bob

Not the solution you were looking for? Getting a personalized solution is easy.

Ask the Experts
Access more of Experts Exchange with a free account
Thanks for using Experts Exchange.

Create a free account to continue.

Limited access with a free account allows you to:

  • View three pieces of content (articles, solutions, posts, and videos)
  • Ask the experts questions (counted toward content limit)
  • Customize your dashboard and profile

*This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

OR

Please enter a first name

Please enter a last name

8+ characters (letters, numbers, and a symbol)

By clicking, you agree to the Terms of Use and Privacy Policy.