How to compare DataGridView cell data to DataSet cell data - vb.net

Question

In a VB.NET WinForms project I'm working on in VS2013 I am detecting when the user changes something in a cell on the CellValueChanged event. When a row in the DataGridView is found that is different from the DataSet I highlight the row in pink.
In my code though, I only know how to iterate through all of the rows, rather than just compare the row that fired the CellValueChanged event to the DataSet.
Here's my current code:
Private Sub dgvEmployees_CellValueChanged(sender As Object, e As DataGridViewCellEventArgs) Handles dgvEmployees.CellValueChanged
' Pass the row and cell indexes to the method so we can change the color of the edited row
CompareDgvToDataSource(e.RowIndex, e.ColumnIndex)
End Sub
Private Sub CompareDgvToDataSource(ByVal rowIndex As Integer, ByVal columnIndex As Integer)
' Force ending Edit mode so the last edited value is committed
EmployeesBindingSource.EndEdit()
Dim dsChanged As DataSet = EmployeesDataSet.GetChanges()
If Not dsChanged Is Nothing Then
For Each dt As DataTable In dsChanged.Tables
For Each row As DataRow In dt.Rows
For i As Integer = 0 To dt.Columns.Count - 1
Dim currentColor As System.Drawing.Color = dgvEmployees.AlternatingRowsDefaultCellStyle.BackColor
If Not row(i, DataRowVersion.Current).Equals(row(i, DataRowVersion.Original)) Then
Console.WriteLine("Row index: " & dt.Rows.IndexOf(row))
' This works
dgvEmployees.Rows(rowIndex).DefaultCellStyle.BackColor = Color.LightPink
Else
' Need to change the BackColor back to what it should be based on its original alternating row color
End If
Next
Next
Next
End If
End Sub
As you can see, I'm passing the row and column index of the changed cell, so how can I take that and compare it to the specific row and/or cell in the unchanged DataSet?
UPDATE
Nocturnal reminded me that I need to allow for sorting of the DGV, so using row indexes won't work. He offered this as a solution (changed slightly to work with my objects):
If Not dsChanged Is Nothing Then
For Each dtrow As DataRow In dsChanged.Tables("employees").Rows
If DirectCast(dtrow, EmployeesDataSet.employeesRow).employeeID.ToString = dgvEmployees.Rows(rowIndex).Cells("employeeID").Value.ToString Then
For i As Integer = 0 To dsChanged.Tables("employees").Columns.Count - 1
If Not dtrow(i, DataRowVersion.Current).Equals(dtrow(i, DataRowVersion.Original)) Then
Console.WriteLine("Employees ID: " & DirectCast(dtrow, EmployeesDataSet.employeesRow).employeeID)
dgvEmployees.Rows(rowIndex).Cells(columnIndex).Style.BackColor = Color.LightPink
Else
' Need to change the BackColor back to what it should be based on its original alternating row color
End If
Next
End If
Next
End If
However, I'm getting an error on the If DirectCast... line saying "Column named "employeeID" cannot be found." I'm not sure if the error is on the DataSet or on the DGV, but there is an employeeID column in the database and DataSet. There is an employeeID as a bound column for the DataGridView, but it is set to Visible = False. That's the only thing I can think of that could possibly cause that error, but if it's a bound column, I would think it could be compared against as in this case.
FINAL WORKING VERSION
Private Sub dgvEmployees_CellValueChanged(sender As Object, e As DataGridViewCellEventArgs) Handles dgvEmployees.CellValueChanged
' Pass the row and cell indexes to the method so we can change the color of the edited row
CompareDgvToDataSource("employees", e.RowIndex, e.ColumnIndex)
End Sub
Private Sub CompareDgvToDataSource(ByVal dataSetName As String, ByVal rowIndex As Integer, ByVal columnIndex As Integer)
' Takes a dataset and the row and column indexes, checks if the row is different from the DataSet and colors the row appropriately
EmployeesBindingSource.EndEdit()
Dim dsChanges As DataSet = EmployeesDataSet.GetChanges()
If Not dsChanges Is Nothing Then
For Each dtrow As DataRow In dsChanges.Tables("employees").Rows
If DirectCast(dtrow, EmployeesDataSet.employeesRow).employeeID.ToString = dgvEmployees.Rows(rowIndex).Cells("employeeID").Value.ToString Then
For i As Integer = 0 To dsChanges.Tables("employees").Columns.Count - 1
If dtrow.RowState.ToString = DataRowState.Added.ToString Then
' TODO: Color entire new row
ElseIf dsChanges.Tables(dataSetName).Rows(0).HasVersion(DataRowVersion.Original) Then
If Not dtrow(i, DataRowVersion.Current).Equals(dtrow(i, DataRowVersion.Original)) Then
Console.WriteLine("Employees ID: " & DirectCast(dtrow, EmployeesDataSet.employeesRow).employeeID)
dgvEmployees.Rows(rowIndex).Cells(columnIndex).Style.BackColor = Color.LightPink
Else
' TODO: Need to change the BackColor back to what it should be based on its original alternating row color
End If
End If
Next
End If
Next
End If
End Sub
My project has four DGVs in it, so this will eventually be expanded to allow for all four DGVs to be checked for changes.

Answer 1

have a look at this approach it is simlar but only iterating the specific Table
Private Sub dgvEmployees_CellValueChanged(sender As Object, e As DataGridViewCellEventArgs) Handles dgvEmployees.CellValueChanged
' Pass the row and cell indexes to the method so we can change the color of the edited row
CompareDgvToDataSource(e.RowIndex, e.ColumnIndex, sender.DataSource.datamember.ToString)
End Sub
and comparing the ID of the given Table
Private Sub CompareDgvToDataSource(ByVal rowIndex As Integer, ByVal columnIndex As Integer, tablename As String)
EmployeesBindingSource.EndEdit()
Dim dsChanged As DataSet = EmployeesDataSet.GetChanges()
If Not dsChanged Is Nothing Then
For Each dtrow As DataRow In dsChanged.Tables(tablename).Rows
If DirectCast(dtrow, EmployeesDataSet.EmployeeRow).EmployeeID = dgvEmployees.Rows(rowIndex).Cells("EmployeeID").Value Then
Dim currentColor As System.Drawing.Color = dgvEmployees.AlternatingRowsDefaultCellStyle.BackColor
For i As Integer = 0 To dsChanged.Tables(tablename).Columns.Count - 1
If Not dtrow(i, DataRowVersion.Current).Equals(dtrow(i, DataRowVersion.Original)) Then
Console.WriteLine("Employees ID: " & DirectCast(dtrow, EmployeesDataSet.EmployeeRow).EmployeeID)
' This works
dgvEmployees.Rows(rowIndex).Cells(columnIndex).Style.BackColor = Color.LightPink
Else
' Need to change the BackColor back to what it should be based on its original alternating row color
End If
Next
End If
Next
End If
End Sub
and i am only changing the backcolor of the cell that was changed not the entire row....but depends how you would use that information anyways
EDIT:
with
Console.WriteLine(EmployeesDataSet.Employee(rowIndex)(columnIndex, DataRowVersion.Original).ToString())
Console.WriteLine(EmployeesDataSet.Employee(rowIndex)(columnIndex, DataRowVersion.Current).ToString())
you can see Current and Original Values
123456