Items collection cannot be modified when the DataSource property is set

I received the following error "Items collection cannot be modified when the DataSource property is set" when populating the combo box with data table.

Reason:

The Items.Clear method was called while the combo box's data source was assigned.

Solution:


Need to set the combo box's data source to nothing before calling Items.Clear method

The following sample code explains this scenario clearly.

Private Sub populatedata()
Dim SQLdta As SqlDataAdapter = Nothing

Try


Dim SQl As String = "SELECT AlertID, alertName FROM alert_Master"
SQLdta  = New SqlDataAdapter(SQl, SConnectionString)

Dim dt As New DataTable

SQLdta.Fill(dt)

cmbProducts.DataSource = Nothing // Need to set the data source nothing
// Comment this line to reproduce the error

cmbtype.Items.Clear()

cmbtype.DataSource = dt


cmbtype.DisplayMember = "Name"


cmbProducts.ValueMember = "ID"

Catch ex As Exception


msgbox(ex.Message)
End Try
End Sub