Question

I never worked with ajax.

I need to know if it is possible to use ajax to run a query on the db (sql server 2005).

My target is to run a query with refreshing the page.

Have you got any ideas?

Answer 1

As MarkusQ has said, it is not possible to do this directly, but you can call a web service or page method to perform the database query and return the result to the client side.

Something like this for a Page Method (this is off the top of my head and untested. I’m also making the assumption you’re using asp.net 3.5)

public partial class _Default : Page  {   [WebMethod]   public static string PerformDatabaseQuery()   {       using (SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings['myConnectionString'].ConnectionString)       {           using (SqlCommand cmd = con.CreateCommand())           {               cmd.CommandText = 'SELECT records FROM myTable';               cmd.CommandType = CommandType.Text;                con.Open();                SqlDataReader reader = cmd.ExecuteReader();               StringBuilder sb = new StringBuilder();                while (reader.Read())               {                    sb.Append((string)reader['records']);                     //May want to do some other formatting here               }                return sb.ToString();           }       }   } } 

then call the page method from the client side. I’m going to use jQuery here

$.ajax({   type: 'POST',   url: 'Default.aspx/PerformDatabaseQuery',   data: '{}',   contentType: 'application/json; charset=utf-8',   dataType: 'json',   success: function(result) {     //Do something with the returned data   } }); 

You can call it using JavaScript and the JavaScript proxy class that is generated when you set EnablePageMethods = true on the ScriptManager control.

function CallPerformDatabaseQuery() {     PageMethods.PerformDatabaseQuery(onSuccess,onFailed); }  function onSuccess(result,userContext,methodName) {   // Do something with returned data }  function onFailed(error,userContext,methodName) {   alert('An error occurred') }