ASP.Net Server Side Code for redirect to another Page

You can use in the below code in your code block

string spurl = SPContext.Current.Site.Url;              
string scriptText = "alert('Record has Successfully SavedDraft.'); window.location='" + spurl + "/Test/default.aspx'";
System.Web.UI.ScriptManager.RegisterClientScriptBlock(panel4, Page.GetType(), "alertMessage", scriptText, true);


Once user click on the Button then it will redirect to other page.