Question

I’m using a CheckBoxList to define which columns are displayed in a GridView. I populate the CheckBoxList using a query like

select column_name, data_type from information_schema.columns
    where table_name = 'myTable'

After the user has chosen the columns (with various Data Types in them) they wish to display, they press a button and the following snippet of VB code generates the GridView.

For Each item As ListItem In chooseColsList.Items
    If item.Selected Then
        Dim bf As New BoundField()
        'PRODUCES BUGGY RESULTS BECAUSE APPLIED TO ALL BoundFields
        bf.DataFormatString = "{0:dd-MMM-yyyy}"
        bf.ApplyFormatInEditMode = True
        bf.DataField = item.Value
        bf.HeaderText = item.Value
        bf.SortExpression = item.Value
        statusReportGrid.Columns.Add(bf)
    End If
Next

What I want to do is to apply the DataFormatString ONLY to the columns with a ‘date’ Data Type in them. However, I have found no way of programmatically determining the Type of the data in the column being bound, no any way of passing this info to the Control. This information exists in the information_schema, as shown in my query, but I don’t know how to extract that out and use it to dynamically setup my BoundFields. It is important to note that I’m using an SqlDataSource.

I’ve experimented with just about every possible solution I can think of and end up here.

Thanks in advance for your help, it is VERY appreciated 🙂

Answer 1

If you set your check box list like this:

<asp:checkboxlist id="list" runat="server"  
DataTextField="column_name" DataValueField="data_type" DataSourceID="YourDSID" />

You should be able to iterate through the items and check the value of the current Item like so:

For Each item As ListItem In chooseColsList.Items
    If item.Selected Then
        Dim bf As New BoundField()

        If StrComp(item.Value,"date") = 0 Then 'Or however datetime is returned
            bf.DataFormatString = "{0:dd-MMM-yyyy}"
            bf.ApplyFormatInEditMode = True
        End If
        bf.DataField = item.Text
        bf.HeaderText = item.Text
        bf.SortExpression = item.Text
        statusReportGrid.Columns.Add(bf)
    End If
Next