RenderControl and HTMLTextWriter in VB Class

[sifitz]

I am trying to dynamically change properties on an Image and then render the image to the browser. RenderControl looks like it would do the trick but I can't figure out how to use the HTMLTextWriter.

If possible, I would also like perform some functionality like Response.Write but this doesn't appear to work from a class.

The two pieces ofCode that I have tried to use

'=========================

Sub WriteImage()
    Dim m_imgRightLogo As System.Web.UI.WebControls.Image

    m_imgRightLogo = New System.Web.UI.WebControls.Image()
    m_imgRightLogo.ImageUrl = "img/logo.gif"
    m_imgRightLogo.AlternateText = "This is the main logo"

    'This is where the problem is - Object reference not set to an instance of an object
    Dim wrtrHTML As HtmlTextWriter
    m_imgRightLogo.RenderControl(wrtrHTML)
End Sub

'=========================

Sub WriteText()
    'Error here - Name response is not declared
    Response.Write("Here is Some text")
End Sub

Can somebody please explain how to do this?

Thanks Si.

 

[JohnYingling]

Not that this will solve the entire problem but you need to change
Dim wrtrHTML As HtmlTextWriter
to
Dim wrtrHTML As New HtmlTextWriter()

http://www.VBResizer.com

Forms/Controls Resizing/Tabbing Control

http://www.VBCompare.com

Compare Code (Text)

http://www.VBSortGen.com

Generate Sort Class in VB or VBScript

 

[sifitz]

Thanks John,
I tried using the New keyword and I got an error saying that I had the wrong number of arguments so I tried adding an argument which needed to be of type System.IO.TextWriter

So I tried declaring a Textwriter and got more trouble:-

Dim wrtrText As New System.IO.TextWriter()
Dim wrtrHTML As New HtmlTextWriter(wrtrText)
m_imgRightLogo.RenderControl(wrtrHTML)

This Code gave me error New cannot be used on a class that is declared as MustInherit

I just can't find decent examples on how this works.