ASP.net Custom GridView Control - asp.net

Question

I'm working on a custom GridView control and need some help. I can get it to properly spit out what I need if I manually put in the column name. Right now I have 2 problems. The first one is getting the column headers to display dynamically. The second is filling in row items dynamicly.
Default.aspx
<asp:View id="vCreateNew" runat="server">
Content Here (View 2)...
<trac:DataGridView id="gvMain" runat="server" GridLines="Horizontal" AutoGenerateColumns="False" > </trac:DataGridView>
</asp:View>
Default.aspx.vb
Partial Class processes_ProgramTrack_Default
Inherits Citi.CSPaper.Controls.BasePage
Protected Sub ProgramTrackNav_MenuItemClick(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.MenuEventArgs) Handles ProgramTrackNav.MenuItemClick
Dim strSelection As String = ProgramTrackNav.SelectedValue
Dim sqlDataSource As New SqlDataSource()
sqlDataSource.ConnectionString = ConfigurationManager.ConnectionStrings("CSPaperWEBConnectionString").ConnectionString
Select Case strSelection
......
Case "CreateNew"
mlvNav.SetActiveView(vCreateNew)
sqlDataSource.SelectCommand = "SELECT [ProgramNumber], [ProgramName], [ProgramStatus] FROM tblPrgTrackPrograms"
Dim args As New DataSourceSelectArguments
gvMain.DataSource = sqlDataSource.Select(args)
gvMain.DataBind()
........
End Select
End Sub
End Class
GridViewControl.ascx
<%# Control Language="VB" AutoEventWireup="false" CodeFile="GridViewControl.ascx.vb" Inherits="GridViewControl" %>
<asp:GridView ID="GridViewControl" runat="server" >
</asp:GridView>
GridViewControl.ascx.vb
Public Class GridViewControl
Inherits System.Web.UI.UserControl
Private _html As New StringBuilder()
Private _dataSource As IEnumerable
Private _CssClass As String
Private _CellSpacing As String
Public Property DataSource() As IEnumerable
Get
Return _dataSource
End Get
Set(ByVal value As IEnumerable)
_dataSource = value
End Set
End Property
Public Overridable Property CssClass() As String
Get
Return _CssClass
End Get
Set(ByVal value As String)
_CssClass = value
End Set
End Property
Public Overridable Property CellSpacing() As String
Get
Return _CellSpacing
End Get
Set(ByVal value As String)
_CellSpacing = value
End Set
End Property
Private Sub CreateBulletedList()
Dim dataSource As IEnumerable = Nothing
Dim i As Integer = 0
Dim strArr() As String = {"ID", "Name", "Fee"}
Try
dataSource = Me._dataSource
Catch
End Try
If Not (dataSource Is Nothing) Then
_html.Append("<table id=""" & ClientID & """ class=""" & _CssClass & """ CellSpacing=""" & _CellSpacing & """>")
_html.Append("<thead>" & vbCrLf & "<tr>" & vbCrLf)
For Each Item As String In strArr
_html.Append("<th>" & Item & "</th>" & vbCrLf)
Next
_html.Append("</tr>" & vbCrLf & "</thead><tbody>" & vbCrLf)
For Each dataObject As Object In dataSource
_html.Append("<tr>" & vbCrLf)
For i = 0 To 2
_html.Append("<td>" & vbCrLf)
_html.Append(dataObject.Row(i))
_html.Append("</td>" & vbCrLf)
Next
_html.Append("</tr>" & vbCrLf)
Next dataObject
_html.Append("</tbody></table>" & vbCrLf)
End If
End Sub
Public Overrides Sub DataBind()
MyBase.OnDataBinding(EventArgs.Empty)
CreateBulletedList()
End Sub
Protected Overrides Sub Render(ByVal output As HtmlTextWriter)
output.Write(_html)
End Sub
End Class
------------------------------------
| Table Data |
------------------------------------
ID AppName Environment
2 TestApp UAT
3 ServerFileMaint UAT
4 ProgramTrack Development
5 RegZ_Stmnt_Adj Active
6 SecInv Decommission
I do not want to manually code for i = 0 to ..., the upperbound, but want to do this dynamicly. Same way for the headings. The problem I run into is if I don't hard code the upperbound I get an error message stating Cannot find column 3.. I get this when coding a second For Each block to loop through the row contained data.

Answer 1

I think I understand whats going on here, and how to fix it.
The biggest source of confusion for me is this block:
For Each dataObject As Object In dataSource
_html.Append("<tr>" & vbCrLf)
For i = 0 To 2
_html.Append("<td>" & vbCrLf)
_html.Append(dataObject.Row(i))
_html.Append("</td>" & vbCrLf)
Next
_html.Append("</tr>" & vbCrLf)
Next dataObject
If dataSource is a DataSet then this kind of makes sense... but not really because instead you would want to reference Table(0). If dataSource is a DataTable then this kind of makes sense except not really because then you would want to loop through For Each dataObject as DataRow in dataSource.Rows. This doesn't appear to be the case though because you reference dataObject.Row(i).
What you probalby want to do is (in rough/untested code) more like this:
For Each dataObject As DataRow In dataSource.Rows
_html.Append("<tr>" & vbCrLf)
For Each col as DataColumn In dataSource.Columns
_html.Append("<td>" & vbCrLf)
_html.Append(dataObject(col).ToString())
_html.Append("</td>" & vbCrLf)
Next
_html.Append("</tr>" & vbCrLf)
Next
This makes the assumption that dataSource is a DataTable, you are going to loop through all of that tables rows, and then for each row you will loop through all columns in the datatable and get the data in that row for each column and display it.