Load image dynamically on Silverlight

Question

I have a Silverlight app that has to load an image dynamically, depending on the image name. The approach that im taking right now is passing the image name by query string to the page and passing that as a param to the Silverlight objet tag

This is the query string passed

Response.Redirect("Build.aspx?img=" + this.PictureUploader.PostedFile.FileName;

And I try to pass it to Silverlight like this:

<object id="SilverlightObject" data="data:application/x-silverlight-2," type="application/x-silverlight-2" width="100%" height="100%">
      <param name="source" value="Silverlight/iMapsSL.xap"/>
      <param name="onError" value="onSilverlightError" />
      <param name="background" value="white" />
      <param name="minRuntimeVersion" value="3.0.40624.0" />
      <param name="autoUpgrade" value="true" />
      <param name="image" value="<%# Request.QueryString["img"] %>" />
      <a href="http://go.microsoft.com/fwlink/?LinkID=149156&amp;v=3.0.40624.0" style="text-decoration:none">
          <img src="http://go.microsoft.com/fwlink/?LinkId=108181" alt="Get Microsoft Silverlight" style="border-style:none"/>
      </a>
    </object><iframe id="_sl_historyFrame" style="visibility:hidden;height:0px;width:0px;border:0px"></iframe>

in the last param tag with name=image value= Requerst.QueryString

I catch the image inside the Silverlight app like this

private void Application_Startup(object sender, StartupEventArgs e)
    {
        string pictureName = "";

        if (e.InitParams != null && e.InitParams.Count > 0)
        {
            pictureName = e.InitParams["image"];

            this.RootVisual = new MainPage(pictureName);
        }

        else
        {
            this.RootVisual = new MainPage();
        }
    }

And when MainPage starts, I set the image source of the Image control like this

this.Image.Source = new BitmapImage(new Uri(pictureName, UriKind.RelativeOrAbsolute));

But Silverlight loads without an image, any help someone?

Answer 1

You can't set arbitary values to by inventing a param names like "image". InitParams are created by specifying the "initparams" param. The "initparams" value is a comma delimited set of name=value pairs. Hence your code should look like:-

<object id="SilverlightObject" data="data:application/x-silverlight-2," type="application/x-silverlight-2" width="100%" height="100%">
      <param name="source" value="Silverlight/iMapsSL.xap"/>
      <param name="onError" value="onSilverlightError" />
      <param name="background" value="white" />
      <param name="minRuntimeVersion" value="3.0.40624.0" />
      <param name="autoUpgrade" value="true" />
      <param name="initparams" value="image=<%# Request.QueryString["img"] %>" />
      <a href="http://go.microsoft.com/fwlink/?LinkID=149156&amp;v=3.0.40624.0" style="text-decoration:none">
          <img src="http://go.microsoft.com/fwlink/?LinkId=108181" alt="Get Microsoft Silverlight" style="border-style:none"/>
      </a>
    </object><iframe id="_sl_historyFrame" style="visibility:hidden;height:0px;width:0px;border:0px"></iframe>