CODEWITHSUNDEEP
vb.netwinformsdatagridviewbindingdatasource
Dave Lowe
Dave Lowe

Reputation: 11

Binding a datagridview to a datasource using a combobox

I read these before asking:

VB: How to bind a DataTable to a DataGridView?

http://msdn.microsoft.com/en-us/library/fbk67b6z(v=vs.100).aspx

I have a very simple problem. The vb.net winforms project contains several datatables, a combobox and a datagridview.

I can select the datatable to display thus:

datagridview1.datasource = dt1 'or dt2 or dt3

and this works fine.

What I want to do is select the datatable to display from the combobox selection where I have previously defined a combobox collection of items thus:

combobox1.item.add("dt1")
combobox1.item.add("dt2")
combobox1.item.add("dt3")

I placed this line

datagridview.datasource = combobox1.SelectedItem

in the ComboBox1_SelectedIndexChanged event.

This just blanks my datagridview. My initial thought was that this fails because I am passing a string to something that expects an object so I have tried datagridview.datasource = CObj(combobox1.SelectedItem) but with no better result.

What simple thing am I doing wrong?

Upvotes: 0

Views: 193

Answers (3)

Jimi
Jimi

Reputation: 32248

Add your DataTable objects references directly to the ComboBox.Items collection. 

combobox1.DisplayMember = "TableName"
combobox1.DataSource = {dt1, dt2, dt3}
' Or... (DisplayMember value applies anyway)
'combobox1.Items.AddRange({dt1, dt2, dt3})

In the ComboBox SelectionChangeCommitted event handler, set the DataGridView.DataSource: 

Private Sub combobox1_SelectionChangeCommitted(sender As Object, e As EventArgs) Handles combobox1.SelectionChangeCommitted
    dataGridView1.DataSource = DirectCast(combobox1.SelectedItem, DataTable)
End Sub

If you want to use the SelectedIndexChanged event instead, check whether SelectedIndex < 0 and just Return if it is.

Upvotes: 1

D J
D J

Reputation: 937

I usually code in c# but this roundabout method would work:

    If combobox1.SelectedItem = "dt1" Then
        datagridview1.DataSource = dt1
    ElseIf combobox1.SelectedItem = "dt2" Then
        datagridview1.DataSource = dt2
    ElseIf combobox1.SelectedItem = "dt3" Then
        datagridview1.DataSource = dt3
    End If

Upvotes: 0

WSC
WSC

Reputation: 992

Your ComboBox is just a list of strings, so when you do datagridview.datasource = combobox1.SelectedItem you're not actually setting the datasource to a datatable.

What I would do this this in your ComboBox1_SelectedIndexChanged event:

Select Case combobox1.SelectedItem
    Case "dt1"
        datagridview1.datasource = dt1
    Case "dt2"
        datagridview1.datasource = dt2
    Case "dt3"
        datagridview1.datasource = dt3
End Select

Upvotes: 0

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