Datagrids in Win Forms are funky.

Ok... perhaps people only thought datagrids would be for displaying data, cause it doesn't look like much thought was put into using them for data entry.

I have a SQL database. I used to have an Access Front end (.adp) that my users could use to enter data using forms I created. The Network manager cannot explain why this is no longer in existance, but needless to say, I needed to get something for my users to enter data.

So, I figured a Win Form app, with datagrids so it would have a similar look and field. My form uses a dataset with the required tables and DataRelations.

The updates work mostly, but the form is very clunky. And at times it doesn't work well. Here's a link to a screen shot Listbox (1) is where the user selects the photographer to work with. This updates the data in datagrids 2 & 3. As they navigate datagrid 2 datagrid 4 updates. I handle the CurrentCellChanged on each of the datagrids and call this function:

Private Sub dbUpdates()

Dim tempPosition As Integer
Dim tempID As Integer
Dim dsChanges As DataSet
Dim cmPhotog As CurrencyManager = DirectCast(Me.BindingContext(Me.dsPhotographers, "Photographers"), CurrencyManager)
Dim cmCodes As CurrencyManager = DirectCast(Me.BindingContext(Me.dsPhotographers, "Photographers.PhtgToProducts.ProdToCodes"), CurrencyManager)
Dim cmOffsets As CurrencyManager = DirectCast(Me.BindingContext(Me.dsPhotographers, "Photographers.PhtgToOffsets"), CurrencyManager)

Try
 If Me.dsPhotographers.HasChanges Then
  cmPhotog.EndCurrentEdit()
  cmCodes.EndCurrentEdit()
  cmOffsets.EndCurrentEdit()
  dsChanges = Me.dsPhotographers.GetChanges

  'Products
  tempPosition = Me.BindingContext(Me.dsPhotographers, "Photographers.PhtgToProducts").Position
  tempID = Me.dsrvc.ProductsUpdate(dsChanges)
  Me.dsPhotographers.Tables("Products").AcceptChanges()

  If tempID > 0 Then
   Me.dsPhotographers.Tables("Products").Rows(Me.dsPhotographers.Tables("Products").Rows.Count - 1)("ProductID") = tempID
  End If

  'Codes
  tempID = Me.dsrvc.ProductCodesUpdate(dsChanges)
  Me.dsPhotographers.Tables("Codes").AcceptChanges()

  If tempID > 0 Then
   Me.dsPhotographers.Tables("Codes").Rows(Me.dsPhotographers.Tables("Codes").Rows.Count - 1)("ProductPriceID") = tempID
  End If

  'Offsets
  tempID = Me.dsrvc.OffsetsUpdate(dsChanges)
  Me.dsPhotographers.Tables("Offsets").AcceptChanges()

  If tempID > 0 Then
   Me.dsPhotographers.Tables("Offsets").Rows(Me.dsPhotographers.Tables("Offsets").Rows.Count - 1)("OffsetPriceID") = tempID
  End If

  Me.dsPhotographers.AcceptChanges()
  cmPhotog.Refresh()
  cmCodes.Refresh()
  cmOffsets.Refresh()
  Me.BindingContext(Me.dsPhotographers, "Photographers.PhtgToProducts").Position = tempPosition

 End If

Catch ex As Exception
 MsgBox(ex.ToString)
End Try
End Sub

It goes and takes the 3 tables (so far that's all we're updating/modifying) and passes them to the update functions. These functions pass back any database generated IDENTITIES. However, to update and refresh these in the datagrids, I do a Refresh, which resets the selected row in the datagrids. This can be very frustrating for the users who might add an item in Datagrid 2, and then want to add items for that in datagrid 4.

Documentation I've seen online has not been very clear on this subject. In fact I was told that anybody who wants to do this type of project gets a different datagrid first. I think that's sad that MS built this tool, but it's only half finished/functional. What can I do? Am I approaching this wrong? My users are screaming for blood, and I don't want to go back to Access Forms!

I think that the problem lies in that how you do your REFRESH.

When you Do Refresh() on the CurrencyManager it forces repopulation of the bound controls, thus loosing the current selection. – So don’t do this.

It doesn’t matter who is the vendor of the Grid -  Microsoft, DevExpress or Infragistics all of them will behave the same way.

In your case your Grid is bound to DataView (Which implements IBindableList interface).

The IBindableList interface declares the ListChanged event which is used by the Grid  to update itself when bound data is changed.
ListChanged event can be raised with different ListChangedType as argument. When ListChangedType is set to Reset – The Grid looses its current selection and selects the first row.

CurrencyManager.Refresh()
{
    //some code
    RaiseListChanged(new ListChangedEventArgs(ListChangedType.Reset, -1));
}

I hope this helps you.

I personally I never bind a dataset to a grid. I always create custom collections that support ITypedList and IBindableList interfaces.

Raj Tripathi wrote:

In your case your Grid is bound to DataView (Which implements IBindableList interface).

How is it bound to a DataView? This is how I'm binding:

Me.dgProducts.DataSource = Me.dsPhotographers
Me.dgProducts.DataMember = "Photographers.PhtgToProducts"

Me.dgGPCodes.DataSource = Me.dsPhotographers
Me.dgGPCodes.DataMember = "Photographers.PhtgToProducts.ProdToCodes"

qwert231 wrote:

How is it bound to a DataView? This is how I'm binding:

Me.dgProducts.DataSource = Me.dsPhotographers
Me.dgProducts.DataMember = "Photographers.PhtgToProducts"

DataSource property can accept only objects that implement IList and IListSource interfaces.
DataTable delegates this implementation to DataTable.DefaultView. That’s why, when you set DataSource to DataTable (or DataSet and DataMember to “TableName”) DataGrid is actually working with DataView.