Generating/registering client-side scripts on ASP/VB.NET

Question

I am currently in the process of converting old "Web 1.0" code to meet current standards.

Is there a better way to generate and append a client-side script other than appending a plethora of lines to a StringBuilder and then registering it to the page via ClientScript.RegisterStartupScript(Me.GetType(), "startUpScript", strScript)?

Is there any other way (besides putting all of this into a global .js file) that this example can be improved? If including this into the main .js file is the "best practice" alternative, then why?

    Dim lsbScript As New Text.StringBuilder

    lsbScript.Append(vbCrLf)
    lsbScript.Append("<script language=""javascript>""" & vbCrLf)
    lsbScript.Append("<!--" & vbCrLf)

    ...

    lsbScript.Append("//-->" & vbCrLf)
    lsbScript.Append("</SCRIPT>" & vbCrLf)


    If Not ClientScript.IsStartupScriptRegistered("someScript") Then
        ClientScript.RegisterStartupScript(Me.GetType(), "someScript", lsbScript.ToString)
    End If

Answer 1

Yes you can include a .js file in your project. Set it's Build Action (right click the file in your project explorer) to Embedded Resource

For example: common.js

Above the namespace of your server control (or whereever you need it):

[assembly: System.Web.UI.WebResource(
     "MyFullNameSpace.Common.js",
      "text/javascript", PerformSubstitution = true)]

OnPreRender event:

if (!Page.ClientScript.IsClientScriptIncludeRegistered("Common"))
                {
                    string url = Page.ClientScript.GetWebResourceUrl(this.GetType(), "MyFullNameSpace.Common.js");
                    Page.ClientScript.RegisterClientScriptInclude("Common", url);
                }

Beware to replace MyFullNameSpace with the complete and exact namespace of where .js is located. If it doesn't work probably .net can't find it and you can use reflector to open your dll and find the .js as embedded resource so you will know the exact namespace it's in.

I always do this from Server Controls but i image it could be done in a web app project as well.

Answer 2

You can get a little mileage out of using AppendLine() instead of concatenating vbCrLf.

Answer 3

a good middle ground might be offloading the script contents to a new js file, and including a script node from codebehind.

protected void Page_Load(object sender, EventArgs e) {

    bool someCondition = Whatever();
    if (someCondition)
    {
        System.Web.UI.HtmlControls.HtmlGenericControl script;
        script = new System.Web.UI.HtmlControls.HtmlGenericControl("script");
        script.Attributes["src"] = "myscript.js";
        this.Controls.Add(script);
    }
}

this will just drop the node at the end of the page. alternatively, you could put a placeholder control whereever you like on the page, and add the new HtmlGenericControl to that.

(sorry, vb is not my native language).