Winform : How to show error icon on empty fields? - vb.net

Question

I have a VB.Net application with forms with some bound fields.
When I type some wrong data in fields, the ErrorProvider shows a red ico automatically.
Is there any way that it shows the same icon when some required fields are empty ?
Here is the binding code of my controls :
Dim MyDataTable as datatable = GetDT
Me.Control.DataBindings.Add(New Binding(Me.BindingProperty, MyDataTable, FieldName, True, DataSourceUpdateMode.OnValidation))
Function GetDT() As DataTable
Dim DT As New DataTable
Dim i As Integer = 0
DT.Columns.Add(New DataColumn("C1", i.GetType))
DT.Columns(0).AllowDBNull = False
Dim R As DataRow = DT.NewRow
R.Item(0) = 15
DT.Rows.Add(R)
Return DT
End Function
The method ErrorProvider.SetError is not an option since the controls are created in a separate process and do not have access to the ErrorProvider.
Thanks.

Answer 1

You can use a custom class in your case:
Public Class customdatatable
Implements IDXDataErrorInfo
Private _value As String
Public Sub New()
MyBase.New()
End Sub
Public Property C1() As String
Get
Return _value
End Get
Set(ByVal value As String)
_value = value
End Set
End Property
Public Sub GetPropertyError(ByVal name As String, ByVal errorinfo As ErrorInfo) _
Implements IDXDataErrorInfo.GetPropertyError
If (name = "C1" And C1 = "") Then
errorinfo.ErrorText = String.Format("Empty value")
End If
End Sub
Public Sub GetError(ByVal errorinfo As ErrorInfo) Implements IDXDataErrorInfo.GetError
End Sub
End Class
then apply it to your form:
Dim DT = New customdatatable With {.C1 = 5} ''GetDT()
TextEdit1.DataBindings.Add(New Binding("EditValue", DT ,"C1", True))
DxErrorProvider1.DataSource = DT
If you don't care to lose focus control on your textfield just use this in your main.
Dim field2 = GetDT()
TextEdit1.DataBindings.Add(New Binding("EditValue", field2,"C1", True))
DxErrorProvider1.DataSource = field2