Question

I want to alert 1 registering the scripts in this order

ScriptManager.RegisterClientScriptBlock(this, this.GetType(), "a", "alert(a);", true);
ScriptManager.RegisterClientScriptBlock(this, this.GetType(), "b", "var a = 1;", true);

But doing this causes a error saying a is undefined.

I have different controls located in different parts of the page registering scripts, and some of them need to go first and others need to go last.

Is there a way to set order it will render?

Answer 1

No, it’s not possible to define the order in which the RegisterClientScriptBlock methods are called. From the documentation for the ScriptManager.RegisterClientScriptBlock method (emphasis mine):

The script blocks are not guaranteed
to be output in the order they are
registered. If the order of the script
blocks is important, use a
StringBuilder object to gather the
scripts together in a single string,
and then register them all in a single
client script block.

Also, you may want to define a different key (second parameter; "a") for the second invocation of RegisterStartupScriptBlock, since a registered script is uniquely identified by its key. If you’re calling this method with your parameters, ScriptManager won’t register the second script, because another script with the same key ("a") has already been registered.