Web Forms :: Rendering Custom Controls And Viewstate?

Feb 3, 2010

When developing custom controls and using them in ASP.NET, what are the answers to the following?

- What events to use for loading and saving viewstate for controls (is this the same thing as control state?) and also for custom controls?

- Similarly, which events should I use to render controls? Is this PreInit and Load? Is this the same for custom controls?

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I have a simple HttpHandler that generates a dynamic image based on query string parameters and a custom web control that renders an image tag pointing to the handler as its 'src' attribute. All works fine when run in the web server, but at design timethe control displays as the "missing image" icon (red x in a box). The handler is registered in the web.config with a ".ashx" extension. The RenderContents method in the control looks like this:

output.AddAttribute("src", ResolveUrl(string.Format("~/Sparklines.SparkHandler.ashx?stype=pm&w={0}&h={1}&sv={2}&ev={3}&cv={4}&sc={5}&ec={6}&mc={7}&gs={8}",
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[code]...

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I am creating custom server control. I have two classes in project. One is main class that render control and another will be used to render content based on condition.I just want to know how to render content from other classes in main class.For example. This isjust an example.My main class code

[Code]....

My TopLeftPane class

[Code]....

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[Code]....

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tb is defined in OnLoad; On run time it works, but on design time I get error: > Error rendering control. And control is not being rendered.

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[Code]....

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Mar 11, 2010

I have the following class:

[Code]....

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[URL]

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[Code]....

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<div class="box"> [code]....

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[Code]....

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[code]....

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/WebResource.axd?d=kyU2OiYu6lwshLH4pRUCUmG-pzI4xDC1ii9u032IPWwUzMsFzFHzL3veInwslz8Y0&t=634056587753507131

FileInfo is throwing System.ArgumentException: Illegal characters in path.

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I have a custom control in an aspx page that has a property named Size

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protected void btnUpload_Click(object sender, EventArgs e)
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if (fuBannerfile.HasFile)
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;//code here not important
}

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int size = customControlId.Size;

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How do I implement Master/Detail functionality with business objects ? What is the alternate to Dataview in master detail/business objects.

I know its a rather broad question but its worth getting started on something =)

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[Code]....

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[Code]....

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UpdatePanel1 contains dynamic controls and a Treeview,

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Now here is the weird thing. First i am running it locally on the built in vs2008 web server.I load my control in fine, do a postback from a linkbutton, locally on my machine it all works fine, no issue.However when it goes onto my host, it falls over with the message:

Failed to load viewstate. The control tree into which viewstate is being loaded must match the control tree that was used to save viewstate during the previous request.Now i also load controls dynamically and use postbacks and things in the admin area of the site...and that works fine, however my front end just keeps failing? See the code behing below:

[Code]....

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