Cannot access embedded resource in asp.net

Question 1

In the Default.aspx.cs file of your example project, change this.GetType() to typeof(_Default):

Page.ClientScript.RegisterClientScriptInclude("JScript1",
    Page.ClientScript.GetWebResourceUrl(typeof(_Default), "EmbeddedResources.JScript1.js"));

Similarly, in the PaymentHistory.ascx.cs file, change this.GetType() to typeof(PaymentHistory):

image1.ImageUrl = Page.ClientScript.GetWebResourceUrl(
    typeof(PaymentHistory), "TestWebApp.Resources.Images.loading.gif");

Explanation: GetWebResourceUrl looks at the type argument to determine which assembly contains the embedded resource. Specifying this.GetType() as the type is incorrect because, in an .aspx or .ascx code-behind class, this.GetType() refers not to that class but rather to the derived class that gets dynamically generated from the .aspx or .ascx markup. This derived class resides in a separate assembly, so GetWebResourceUrl can't find the embedded resource.

Question 2

Is the resource in a separate project or in the same project as your User Control? If separate you have to substitute this.GetType() with an object's GetType() function that resides in the separate project.

If in the same project, just do Page.GetType(), because you want a reference to the page and not the user control

Question 3

First of all, the type that you are passing to the GetWebResourceUrl call (or to the RegisterClientScriptResource I show below) is actually there to point to which assembly contains your resource. The problem is that "this.GetType()" is returning a type that is not in the current executing assembly (as strange as that may be).

The following 2 lines demonstrate the issue.

        Response.Write(this.GetType().Assembly.FullName + "<br>");
        Response.Write(Assembly.GetExecutingAssembly().FullName + "<br>");

The first line returns the name of a "App_Web_??????" assembly. The second returns the expected "EmbeddedResources" assembly.

In the call below, I just pass in the first type I get back from the executing assembly and the call works. Page.ClientScript.RegisterClientScriptResource(Assembly.GetExecutingAssembly().GetTypes()[0], names[0]);

this.GetType() actually returns a type that the web server creates that inherits from your type. That is why typeof(_Default) would also work to designate the correct assembly.

Question 4

Here you can see a code in Vb.NET that uses the Reflection library to detect the current Assembly Name and the current NameSpace.

If you concatenate the namespace with embedded image name, you can use the command Page.clientScript.GetWebResourceURL to generate a link for image as you see in first function

In second function, you see a loop in all of resources name until find the complete name of embedded resouce.

Friend Class ReadResources

    ' Get our assembly.
    Private Shared executingAssembly As System.Reflection.Assembly = Reflection.Assembly.GetExecutingAssembly()

    ' Get our namespace.
    Private Shared myNamespace As String = executingAssembly.GetName().Name.ToString()

    ''' <summary>
    ''' Generate resource link
    ''' </summary>
    Friend Shared Function GetResourceLink(ByVal ref As String,
                                           ByVal obj As Object,
                                           ByVal page As Web.UI.Page) As String
        Dim out As String = Nothing
        out = Page.ClientScript.GetWebResourceUrl(obj.GetType, myNamespace & "." & ref)

        If out Is Nothing OrElse out.Length <= 0 Then
            out = FindResource(ref, obj)
        End If

        Return out
    End Function

    Friend Shared Function FindResource(ByVal reference As String,
                                        ByVal obj As Object) As String
        Dim out As String = ""
        For Each embedded In obj.GetType().Assembly.GetManifestResourceNames()
            If embedded.Contains(reference) Then
                out = embedded
                Exit For
            End If
        Next
        Return out
    End Function


End Class