How can I force a DataGridView to redraw?

问题

I have a DataGridView which uses a BindingSource. This BindingSource points to a read-only property, which is a collection of department objects. When I programmatically add a department to the property, I am having trouble getting the DataGridView to redraw itself + show the new department.

If I set a breakpoint, I verify that the property has the new department; yet the DataGridView does not draw it. If I navigate away from the tab, and then back, the DataGridView displays the new department.

My question is essentially, how can I programmatically trigger whatever happens when I navigate away from and then back to the DataGridview, to force it to redraw (or force its BindingSource to update)? I've tried all the following:

AffectedDepartmentsBindingSource.CancelEdit()
AffectedDepartmentsBindingSource.EndEdit()
AffectedDepartmentsBindingSource.ResetBindings(False)
AffectedDepartmentsBindingSource.ResetBindings(True)

AffectedDepartmentsDataGridView.Refresh()
AffectedDepartmentsDataGridView.Update()
AffectedDepartmentsDataGridView.Hide()
AffectedDepartmentsDataGridView.Show()

---

Here's the property:

Public ReadOnly Property affectedDepartments As SortableBindingList(Of Department)
    Get
        Dim uniqueDeptIds As New ArrayList
        Dim _affectedDepartments As New SortableBindingList(Of Department)

        'Go through products
        For Each p As product In products.Where(Function(pr) pr.isNotACopy)
            If Not uniqueDeptIds.Contains(p.cs_dept_id) Then
                uniqueDeptIds.Add(p.cs_dept_id)
                Dim d As New Department With {
                    .schedule = Me,
                    .name = p.department,
                    .cs_dept_id = p.cs_dept_id
                }
                _affectedDepartments.Add(d)
            End If
        Next

        'Add temp departments
        If _tempDepartment IsNot Nothing Then
            _affectedDepartments.Add(_tempDepartment)
        End If

        Return _affectedDepartments
    End Get
End Property

回答1:

Like this:

Me.DataGridView1.Invalidate()

Edit

The reason why you don't see the added items is because you create a new instance each time.

You should do it like this:

Public ReadOnly Property affectedDepartments As SortableBindingList(Of Department)
    Get

        Dim uniqueDeptIds As New ArrayList

        If (_affectedDepartments Is Nothing) Then
            _affectedDepartments = New SortableBindingList(Of Department)
        End If

        'Go through products
        For Each p As product In products.Where(Function(pr) pr.isNotACopy)
            If Not uniqueDeptIds.Contains(p.cs_dept_id) Then
                uniqueDeptIds.Add(p.cs_dept_id)
                Dim d As New Department With {
                    .schedule = Me,
                    .name = p.department,
                    .cs_dept_id = p.cs_dept_id
                }
                _affectedDepartments.Add(d)
            End If
        Next

        'Add temp departments
        If _tempDepartment IsNot Nothing Then
            _affectedDepartments.Add(_tempDepartment)
        End If

        Return _affectedDepartments

    End Get
End Property

Private _affectedDepartments As SortableBindingList(Of Department)

回答2:

you can refresh the DataGridView

Datagrid.Items.Refresh()

来源：https://stackoverflow.com/questions/20843313/how-can-i-force-a-datagridview-to-redraw