Gridview CustomUnboundColumnData Date column with custom strings filter error

Question

I have a column with dates and strings in my table (varchar) named DateColumn and i want to show it as dates to be able to filter by date. I first tried to create an unbound column with unboundexpression with GetData(DateColumn) and it worked, all the strings with dates where converted to date and the other was #Err. And i was able to filter by date. but i wanted to control these #Err: its empty? its "otherstring"? or its something other? so i tried with CustomUnboundColumnData function:

           Try
               value = Date.Parse(view.GetListSourceRowCellValue(listSourceRowIndex, columna))
           Catch ex As Exception
               If IsDBNull(view.GetListSourceRowCellValue(listSourceRowIndex, columna)) Then
                   value = DBNull.Value
               Else
                   If view.GetListSourceRowCellValue(listSourceRowIndex, columna) = "" Then
                       value = DBNull.Value
                   ElseIf view.GetListSourceRowCellValue(listSourceRowIndex, columna) = "otherstring" Then
                       value = "#otherstring"
                   Else
                       value = "#Err"
                   End If
               End If

           End Try

but now when I try to filter by value (by date) i get an error:

Cannot compare two items in array.: System.ArgumentException: The object must be of type String.

if I replace the "#Err" and "#otherstring" for DBNull.Value it works again. but i need to be able to put other strings.

It's not quite clear what you are trying to do. Please show one or two sample data and tell what the expected behavior is based on the sample data. — Reza Aghaei, Jan 17 '22 at 00:10

score 0 · Answer 1 · answered Jan 16 '22 at 23:55

Don't use the Try...End Try for fully expected errors. You are not using ex at all.

Use a TryParse. You can distinguish the nulls and other strings by assigning an obviously bogus date. Create a list of the bad strings for review.

    Dim d As Date
    Dim value As Date
    Dim errList As New List(Of String)
    If Date.TryParse(View.GetListSourceRowCellValue(listSourceRowIndex, columna), d) Then
        value = d
    ElseIf IsDBNull(View.GetListSourceRowCellValue(listSourceRowIndex, columna)) Then
        value = CDate("January 2, 0001 ")
    ElseIf View.GetListSourceRowCellValue(listSourceRowIndex, columna) = "" Then
        value = CDate("January 2, 0001 ")
    Else
        value = CDate("January 1, 0001")
        errList.Add(View.GetListSourceRowCellValue(listSourceRowIndex, columna).ToString)
    End If

Gridview CustomUnboundColumnData Date column with custom strings filter error

1 Answers1