aspnet-403757-troubleshooting-server-side-issues-could-not-find-control-in-controlparameter.md
The error occurs in the following scenario if the ControlParameter.ControlID value is incorrect:
Make sure the ControlParameter.ControlID value equals a control’s Control.UniqueID property value.
Use the control’s Init event (How To: Use the Init/Load event handler) to find its unique ID and assign it to the ControlParameter.ControlID property.
<dx:ASPxComboBox ID="ASPxComboBox1" runat="server" DataSourceID="AccessDataSource1"
ValueType="System.Int32" ValueField="CategoryID"
TextField="CategoryName" OnInit="ASPxComboBox1_Init">
...
</dx:ASPxComboBox>
protected void ASPxComboBox1_Init(object sender, EventArgs e) {
ASPxComboBox control = (ASPxComboBox)sender;
System.Diagnostics.Debug.WriteLine(control.UniqueID); // It can be ASPxPanel1$ASPxComboBox1, ASPxGridView1$Title$ASPxComboBox1, etc.
}
Protected Sub ASPxComboBox1_Init(ByVal sender As Object, ByVal e As EventArgs)
Dim control As ASPxComboBox = CType(sender, ASPxComboBox)
System.Diagnostics.Debug.WriteLine(control.UniqueID)
End Sub