Question

This is a VB.NET, Winforms App. I have a datagridview on “Form1” that uses a databinding.datasource which is an Entity Framework table. I fill the datagridview with the below function on Form1:

Sub PM_UnitViewGrid()
    Try

        _form1.UnitsBindingSource.DataSource = db.units.Where(Function(f) f.propertyId = _form1.CurrentPropertyId).OrderBy(Function(F) F.unitNumber)
        _form1.UnitDataGridView.DataSource = _form1.UnitsBindingSource.DataSource
        Dim iCount As Integer = _form1.UnitDataGridView.RowCount
        For x As Integer = 0 To iCount - 1
            If Not IsNothing(_form1.UnitDataGridView.Rows(x).Cells(4).Value) Then
                Dim tid As Integer = _form1.UnitDataGridView.Rows(x).Cells(4).Value
                Dim _ten As tenant = db.tenants.Single(Function(f) f.Occupantid = tid)
                _form1.UnitDataGridView.Rows(x).Cells(1).Value = _ten.first_name + ", " + _ten.last_name
            Else
                Dim btnColumn As DataGridViewButtonCell = CType(_form1.UnitDataGridView.Rows(x).Cells(1), DataGridViewButtonCell)
                btnColumn.Style.BackColor = Color.Green
                _form1.UnitDataGridView.Rows(x).Cells(1).Value = "VACANT"
            End If
        Next

    Catch ex As Exception
        MessageBox.Show(ex.Message)
    End Try

    Return
End Sub

This works great and also assigns the needed values to an unbound column. The problem is that the cells(1) is a button. Which when clicked takes the user to another form as a new dialog window. The function for which is below. However, once the changes are made in that form I need for the datagridview to refresh the data that its using from the database and show the correct data. As it stands right now the values are not updating on the datagridview unless the app is completely exited and restarted. Nothing I have found seems to work and Refresh and Update only redraw the control. I need the underlying datasource to refresh and then the datagridview once the child form is exited.. This has had me stumped for a good 36 hours now and I am lost as to why nothing I am trying is working. ANY and all help would be greatly appreciated.

The sub that loads the child form based on the cells(1) button clicked is as follows:

Private Sub UnitDataGridView_CellContentClick(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles UnitDataGridView.CellContentClick
    UnitDataGridView.CommitEdit(DataGridViewDataErrorContexts.CurrentCellChange)
    Dim y As DataGridViewCellEventArgs = e
    Dim Tid As Integer = Nothing
    If e.ColumnIndex = 1 Then
        If Not e.RowIndex = -1 Then
            If Not IsNothing(UnitDataGridView.Rows(e.RowIndex).Cells(4).Value) Then
                currentTenent = UnitDataGridView.Rows(e.RowIndex).Cells(4).Value
                TenentIdentification = currentTenent
                If Not IsNothing(e) Then
                    If Not IsNothing(UnitDataGridView.Rows(e.RowIndex).Cells(4).Value) Then
                        Tid = UnitDataGridView.Rows(e.RowIndex).Cells(4).Value
                        Dim _ten As tenant = db.tenants.Single(Function(f) f.Occupantid = Tid) 'tenant is a table entity 
                        TenantViewSubs.tenId = _ten.Occupantid
                        Dim t As New TenantView
                        t.tenId = tid
                        t.ShowDialog()
                    End If
                End If

                PropertyManagSubs.PM_UnitViewGrid() 'This is the function that is above that fills the datagridview
            Else
                Dim uTview As New UnassignedTenants
                uTview.selectedProperty = selectedProperty 'selectedProperty is Integer 
                uTview.ShowDialog()

                PropertyManagSubs.PM_UnitViewGrid() 'This is the function that is above that fills the datagridview
            End If
        End If
    End If
End Sub 

I tried each of the following code blocks after the t.ShowDialog() line with no change at all.

UnitDataGridView.Refresh()

.

UnitsBindingSource.Dispose()
UnitsBindingSource.DataSource = db.units.Where(Function(f) f.propertyId = selectedProperty).OrderBy(Function(f) f.unitNumber)
UnitDataGridView.DataSource = UnitsBindingSource.DataSource

.

UnitsBindingSource.DataSource = nothing
unitsBindingSource.DataSource = db.units.Where(Function(f) f.propertyId = selectedProperty).OrderBy(Function(f) f.unitNumber)
UnitDataGridView.DataSource = UnitsBindingSource.DataSource

Answer 1

I finally fixed this on my own.. It was in the way I passed my db context to the databinding..

I simply wrote the below sub:

Private Sub UpdateValues()
    Dim context As New storageEntities 'storageEntities is an Entity
    Dim query = context.units.Where(Function(F) F.propertyId = selectedProperty).OrderBy(Function(f) f.unitNumber)
    UnitDataGridView.DataSource = query
End Sub

Then anytime a child form updated data I simply call

  UpdateValues()

After the dialog box closes.

This may help someone else with the same problems so that is why I am posting it.