Will this class cause memory leaks, and does it need a dispose method? (asp.net vb)
- by Phil
Here is the class to export a gridview to an excel sheet:
Imports System
Imports System.Data
Imports System.Configuration
Imports System.IO
Imports System.Web
Imports System.Web.Security
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Web.UI.WebControls.WebParts
Imports System.Web.UI.HtmlControls
Namespace ExcelExport
Public NotInheritable Class GVExportUtil
Private Sub New()
End Sub
Public Shared Sub Export(ByVal fileName As String, ByVal gv As GridView)
HttpContext.Current.Response.Clear()
HttpContext.Current.Response.AddHeader("content-disposition", String.Format("attachment; filename={0}", fileName))
HttpContext.Current.Response.ContentType = "application/ms-excel"
Dim sw As StringWriter = New StringWriter
Dim htw As HtmlTextWriter = New HtmlTextWriter(sw)
Dim table As Table = New Table
table.GridLines = GridLines.Vertical
If (Not (gv.HeaderRow) Is Nothing) Then
GVExportUtil.PrepareControlForExport(gv.HeaderRow)
table.Rows.Add(gv.HeaderRow)
End If
For Each row As GridViewRow In gv.Rows
GVExportUtil.PrepareControlForExport(row)
table.Rows.Add(row)
Next
If (Not (gv.FooterRow) Is Nothing) Then
GVExportUtil.PrepareControlForExport(gv.FooterRow)
table.Rows.Add(gv.FooterRow)
End If
table.RenderControl(htw)
HttpContext.Current.Response.Write(sw.ToString)
HttpContext.Current.Response.End()
End Sub
Private Shared Sub PrepareControlForExport(ByVal control As Control)
Dim i As Integer = 0
Do While (i < control.Controls.Count)
Dim current As Control = control.Controls(i)
If (TypeOf current Is LinkButton) Then
control.Controls.Remove(current)
control.Controls.AddAt(i, New LiteralControl(CType(current, LinkButton).Text))
ElseIf (TypeOf current Is ImageButton) Then
control.Controls.Remove(current)
control.Controls.AddAt(i, New LiteralControl(CType(current, ImageButton).AlternateText))
ElseIf (TypeOf current Is HyperLink) Then
control.Controls.Remove(current)
control.Controls.AddAt(i, New LiteralControl(CType(current, HyperLink).Text))
ElseIf (TypeOf current Is DropDownList) Then
control.Controls.Remove(current)
control.Controls.AddAt(i, New LiteralControl(CType(current, DropDownList).SelectedItem.Text))
ElseIf (TypeOf current Is CheckBox) Then
control.Controls.Remove(current)
control.Controls.AddAt(i, New LiteralControl(CType(current, CheckBox).Checked))
End If
If current.HasControls Then
GVExportUtil.PrepareControlForExport(current)
End If
i = (i + 1)
Loop
End Sub
End Class
End Namespace
Will this class cause memory leaks? And does anything here need to be disposed of? The code is working but I am getting frequent crashes of the app pool when it is in use.
Thanks.
