error after run webservice in url

hello

i write a webservice.
when i run it in localhost it work fine.
but after upload it in my host, it also work (register data in db). but show a error.

here is error message:
Server Error in '/' Application.
Object reference not set to an instance of an object.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:


[NullReferenceException: Object reference not set to an instance of an object.]
DOAdverisingModule.AdsModule.context_PostRequestHandlerExecute(Object sender, EventArgs e) +295
System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +141
System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step) +48
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +71

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.7.3163.0


--------------------------------------------------------------
here is code of webservice
[WebMethod]
public void insert_into_test_tbl(string name, int grade)
{
con = new SqlConnection(conString);
SqlCommand cmd = con.CreateCommand();
SqlTransaction tr;


string comm = "insert into test_tbl (name, grade) VALUES(N'" +
name + "', " +
grade + ") ";

cmd.CommandText = comm;

if (con.State == ConnectionState.Closed)
con.Open();

tr = con.BeginTransaction();
cmd.Transaction = tr;
cmd.ExecuteNonQuery();
tr.Commit();

}

thanks

Please use appropriate formatting tags to aid readability.

Quote:

---

Originally Posted by armm1388

hello

i write a webservice.
when i run it in localhost it work fine.
but after upload it in my host, it also work (register data in db). but show a error.

here is error message:

Quote:

---

Server Error in '/' Application.
Object reference not set to an instance of an object.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:


[NullReferenceException: Object reference not set to an instance of an object.]
DOAdverisingModule.AdsModule.context_PostRequestHandlerExecute(Object sender, EventArgs e) +295
System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +141
System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step) +48
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +71

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.7.3163.0

---

--------------------------------------------------------------
here is code of webservice

Code:

---

        [WebMethod]
        public void insert_into_test_tbl(string name, int grade)
        {
            con = new SqlConnection(conString);
            SqlCommand cmd = con.CreateCommand();
            SqlTransaction tr;


            string comm = "insert into test_tbl (name, grade) VALUES(N'" +
                name + "', " +
                grade + ") ";

            cmd.CommandText = comm;

            if (con.State == ConnectionState.Closed)
                con.Open();

            tr = con.BeginTransaction();
            cmd.Transaction = tr;
            cmd.ExecuteNonQuery();
            tr.Commit();

        }

---

thanks

---

Exactly as the exception states, a NullReferenceException is being thrown on line 295 in DOAdverisingModule.AdsModule.context_PostRequestHandlerExecute. A NullReferenceException occurs when you try to access a member of an object via a variable or other reference that is null. You should spend some time learning how to read an exception stack trace.