title: select dropdownlist value and display gridview from different tables ASP.NET
body: <p>I create web application. I add drop down list. I connect list with Names of Tables Categories. for example 1, 2, 3. When I select value 1 it should be created grid view populated with data from Table 1. When I select 2 create grid view populated with data from Table 2.. 
  I connect tables in the SQL database. PrimaryKey Category ID, foreign key1, foreign key2 approprietly.</p>
  
  <p>I know how to populate grid view by select value in the drop down list, but the values from one table. In this case I have 4 tables and I don't know how to realise that. Is there somebody who can help me? by some tutorial, or piece of code? thanks</p>