GUID Problem in C#...

Question

 helloo,
 
i am having sum problem in the function below...this function is use to get UID from UserName in which i m firng select query to get UID from DB........

But SqlReader is not able retireve the Value of tht...it is giving sum Type casting error...

The Field UID DataType is GUID ...


 public Guid GetUIDFromUserName(string p_UserName)

{

guid RetInt = new guid();

SqlConnection SqlConn = new SqlConnection();

SqlCommand SqlCmd = new SqlCommand();

SqlDataReader SqlRead;

Guid RetInt = new Guid();

SqlConn.ConnectionString = m_DM.GetConnectionString("PIMS_DB");

SqlConn.Open();

SqlCmd.CommandText = "Select UID from UserTran1 where UserName Like " + m_DM.MakeQryFieldStr(p_UserName);

SqlCmd.Connection = SqlConn;

SqlRead = SqlCmd.ExecuteReader();

if (SqlRead.HasRows == true)

{

SqlRead.Read();

RetInt = (Guid)SqlRead.GetGuid(0); //// Error generates Here.....

}

return RetInt;

}


It generates Sum Error

'Specified cast is not valid.'

Kindly help me.. Plz..........................

Answer 1

If I'm not mistaken, GetGuid() already returns a Guid. you dont have to explicity typecast the RHS.
anyways I think you are getting an error because the value returned is null (DbNull i.e.).
check for that and then do the assignment. Might resolve your issue.

Answer 2

It is not your cast that is failing, you don't need a cast because GetGuid already returns a Guid.  It is a cast inside of GetGuid() that fails.  Perhaps because it is casting a DBNull to a Guid.  Use something like this to see what is going on:

  object value = SqlRead[0];

And inspect "value" in the debugger.

---

Hans Passant.

Answer 3

Hey Thanxxsss

Mr.Praveeen & Mr. Hans......

U made my Programming Night.....


Regards

Tushar