Question

I’m completely new to working with JavaScript in ASP .NET so bear with me.

Say I have the following:

protected void btnCreateReplication_Click(object sender, EventArgs e)
{
   try
   {
      doSomething();
   }
   catch (Exception ex)
   {
      //How do I display the error? I know if I were in WinForms, I could just do this:
      MessageBox.Show(ex.Message); 
   }
}

First question:

1. Should I put all of my JavaScript code in a .js file in my ASP .NET solution?
2. If so, how do I call an alert message from the .js file?
3. If not, how do I call an alert message instead of the MessageBox.Show?

Answer 1

You’ll have to use the Page.ClientScript.RegisterClientScriptBlock method.

string script = "alert('We had an error')";
Page.ClientScript.RegisterClientScriptBlock(GetType(), 
    "myErrorKey", script, true);

RegisterClientScriptBlock takes a type, a key to see if the script block is already registered, the script, and a boolean indicating whether the method should add the script tags, or if you’re string script variable already includes them.