Datagridview auto calculate columns.

Need Help. I have a Datagridview that have the following columns.

1. ID
2. Products
3. Qty
4. UnitPrice
5. Total

The Products column is a combobox. The products combobox when selected will autofill the UnitPrice column. I have subroutine (GetOtherFeeAmount) that will get the UnitPrice from the database according to the item selected from the Products combobox.

The Problem: I get this error "Conversion from type 'DataRowView' to type 'Long' is not valid." The initial first row data entry is ok. I will always get this error everytime I go back and change a combobox selection.

This is where the error occurs highlighted in RED:

Code:

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    Private Sub ComboBox_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)

        Dim comboBox As ComboBox = CType(sender, ComboBox)

        If comboBox IsNot Nothing Then
            Dim cdecUnitPrice As Decimal
            cdecUnitPrice = GetOtherFeeAmount(GetDefaultSchoolYearOrSemester("School Year"), GetDefaultSchoolYearOrSemester("Semester Name"), comboBox.SelectedValue)
            dgvFees("UnitPrice", dgvFees.CurrentRow.Index).Value = cdecUnitPrice
            dgvFees("FeeAmount", dgvFees.CurrentRow.Index).Value = CInt(dgvFees("Qty", dgvFees.CurrentRow.Index).Value) * CDec(dgvFees("UnitPrice", dgvFees.CurrentRow.Index).Value)
        End If


    End Sub

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My EditingControlShowing Code:

Code:

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    Private Sub dgvFees_EditingControlShowing(sender As Object, e As System.Windows.Forms.DataGridViewEditingControlShowingEventArgs) Handles dgvFees.EditingControlShowing

        If TypeOf e.Control Is DataGridViewComboBoxEditingControl Then
            Dim te As DataGridViewComboBoxEditingControl = DirectCast(e.Control, DataGridViewComboBoxEditingControl)
            te.AutoCompleteMode = AutoCompleteMode.Suggest
            te.AutoCompleteSource = AutoCompleteSource.ListItems
            te.SelectedIndex = -1
            te.DropDownStyle = ComboBoxStyle.DropDownList
            te.FlatStyle = FlatStyle.Flat
        End If


        ''=====check if SLID combobox value is changed =======
        If dgvFees.CurrentCell.ColumnIndex = 1 And Not e.Control Is Nothing Then

            Dim comboBox As ComboBox
            comboBox = CType(e.Control, ComboBox)

            If (comboBox IsNot Nothing) Then
                RemoveHandler comboBox.SelectedIndexChanged, New EventHandler(AddressOf ComboBox_SelectedIndexChanged)

                'Add the event handler.
                AddHandler comboBox.SelectedIndexChanged, New EventHandler(AddressOf ComboBox_SelectedIndexChanged)
            End If

        End If

        '=====code below is to control the user to input correct textbox entry
        If dgvFees.CurrentCell.ColumnIndex = 2 And Not e.Control Is Nothing Then

            Dim tb As TextBox = CType(e.Control, TextBox)
            '---add an event handler to the TextBox control---
            AddHandler tb.KeyPress, AddressOf TextBox_KeyPress

        End If

    End Sub

---

My CellEndEdit Code:

Code:

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    Private Sub dgvFees_CellEndEdit(sender As Object, e As System.Windows.Forms.DataGridViewCellEventArgs) Handles dgvFees.CellEndEdit

        If dgvFees.CurrentCell.ColumnIndex = 2 Then

            Dim row As DataGridViewRow = dgvFees.Rows(e.RowIndex)

            Dim QtyValue As Decimal = row.Cells("Qty").Value
            Dim UnitPriceValue As Decimal = row.Cells("UnitPrice").Value
            Dim TotalAmountValue As Decimal = QtyValue * UnitPriceValue

            row.Cells("FeeAmount").Value = CDec(TotalAmountValue)

        ElseIf dgvFees.CurrentCell.ColumnIndex = 4 Then
            txtTotal.Text = GetTotal()
        End If

    End Sub

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Any help will be highly appreciated.

Try using something like this in place of the selected value:

Code:

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CType(ComboBox.SelectedValue, DataRowView).Item('whatever index works here.)

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Thanks for the reply. I got this error. Unable to cast object of type 'System.Int64' to type 'System.Data.DataRowView',

OK. So that means that the Combobox.SelectedValue wasn't the issue after all, because the type of the SelectedValue is a long value like you're expecting.

Not sure where the issue is...

Need to see the code for "GetOtherFeeAmount"

Quote:

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Originally Posted by dolot

OK. So that means that the Combobox.SelectedValue wasn't the issue after all, because the type of the SelectedValue is a long value like you're expecting.

Not sure where the issue is...

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BTW: I edited my post above. I noticed I can add new rows with no errors. The error will only occur if I go back to a combobox and change the selection or cancel a new row.

Quote:

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Originally Posted by coolwater

BTW: I edited my post above. I noticed I can add new rows with no errors. The error will only occur if I go back to a combobox and change the selection or cancel a new row.

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That makes sense, that's when SelectedIndexChanged would be called. GetOtherFeeAmount doesn't seem to like the arguments you send.

If the dgv is bound to a datatable, you can use an expression to autocalculate the Total field

Quote:

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Originally Posted by wes4dbt

Need to see the code for "GetOtherFeeAmount"

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My GetOtherFeeAmount Code:

Code:

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  Private Function GetOtherFeeAmount(intSLID As Long, intSYID As Long, intSemesterID As Long) As Decimal

        Using con As SqlConnection = New SqlConnection(CS)

            Dim da As SqlDataAdapter
            Dim ds As DataSet

            da = New SqlDataAdapter("NET_OtherCharges_GetOtherFeeAmount", con)
            da.SelectCommand.CommandType = CommandType.StoredProcedure
            da.SelectCommand.Parameters.AddWithValue("@SLID", CLng(intSLID))
            da.SelectCommand.Parameters.AddWithValue("@SYID", CLng(intSYID))
            da.SelectCommand.Parameters.AddWithValue("@SemesterID", CLng(intSemesterID))
            da.SelectCommand.CommandTimeout = 60

            ds = New DataSet
            da.Fill(ds)
            ds.Tables(0).TableName = "OtherFees"

            If ds.Tables("OtherFees").Rows.Count > 0 Then
                Return ds.Tables("OtherFees").Rows(0).Item("OtherFeeAmount")
            Else
                Return 0
            End If

        End Using

    End Function

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Thanks for the reply. My dilema is my UnitPrice column (readonly) is dependent on the combobox column. Everytime the combobox selected value is changed the UnitPrice column is also updated. Somehow straight encoding of data is fine. The problem occurs when I go back and change a combobox value or if I cancel a new row.

The error message tells you the problem,

Code:

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Conversion from type 'DataRowView' to type 'Long' is not valid

---

The function GetOtherFeeAmount is expecting all the parameters to be type Long, so one of your parameters is of Type DataRowView. Or it actually could be in GetDefaultSchoolYearOrSemester, I haven't seen that code.

I believe that combobox.Selectedvalue is of Type DataRowView

Quote:

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Originally Posted by wes4dbt

I believe that combobox.Selectedvalue is of Type DataRowView

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That was my first thought as well, but see where that went in posts 2 & 3.