get value of sqlcommand

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hi dear's,
this is my code:

C#

SqlDataReader dReader;
        SqlConnection conn = new SqlConnection(@"Data Source=.\sql2008;Initial Catalog=jelvehsadb;Integrated Security=True;");
        SqlCommand comm = new SqlCommand();
        comm.Connection = conn;

        comm.CommandText = @"Select response from work_with_us where national_code =@CustomerID";
        comm.Parameters.AddWithValue("CustomerID", 00488);  
        comm.Connection.Open();
        

        dReader = comm.ExecuteReader();
          
        if (dReader.HasRows == true)
        {
            TxtShow.Text = ???;
        }
        

    }

my problem is how i can get my response vlaue from dreader??
the result must show on txtshow.
thanks

Posted 23-Sep-13 21:54pm

Member 8453437

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3 solutions

Solution 2

Hello Member,

You can modify your code as shown below.

C#

SqlDataReader dReader;

SqlConnection conn = new SqlConnection(@"Data Source=.\sql2008;Initial Catalog=jelvehsadb;Integrated Security=True;");
SqlCommand comm = new SqlCommand();
comm.Connection = conn;
 
comm.CommandText = @"Select response from work_with_us where national_code =@CustomerID";
comm.Parameters.AddWithValue("CustomerID", 00488);  
comm.Connection.Open();
        
dReader = comm.ExecuteReader();
// The default position of the SqlDataReader is before the first record. 
// Therefore, you must call Read to begin accessing any data.
if (dReader.Read()) {
    TxtShow.Text = dReader.GetString(0);
}

Regards,

Posted 23-Sep-13 22:07pm

Prasad Khandekar

Comments

Member 8453437 24-Sep-13 4:17am

i get this error:
Invalid attempt to read when no data is present.
how i can present data??
thanks

Solution 3

you can do something like this :

C#

SqlDataReader drmax1;
 drmax = comm.ExecuteReader();
                    drmax.Read();
                    TxtShow.Text = System.Convert.ToString((System.Convert.ToInt32(drmax["response"].ToString()));

Posted 23-Sep-13 22:12pm

Pooria Lajevardy

Comments

Member 8453437 24-Sep-13 4:19am

thanks but i get below error
Input string was not in a correct format.

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OriginalGriff · Accepted Answer · 2013-09-23T22:03:00

Try:

C#

if (dReader.Read())
   {
   TxtShow.Text = (string) reader["response"];
   }

"but in step 2 when my sqlcommand return a value,it's not related to the response column,
so i want access to that value is now ready on the datareader,may you help me how i can access to this data,
thanks dera OriginalGriff"

Yes, it is!
When your issue a SELECT, SQL returns all the rows that match the WHILE statement, but only the columns you specify. So if you have a table with three columns:

Id   UserName  UserAddress
7    Fred      Home
8    Joe       Away
9    Bert      Holiday cottage

And you issue a SELECT:

SELECT UserName, UserAddress FROM MyTable WHERE Id=8

Then you need to do two accesses to your DataReader to read each of the two columns of the row that you have asked for:

C#

string userName = (string) reader["UserName"];
string userAddr = (string) reader["UserAddress "];

In your case, you are asking for (I assume) a single row (where the national_code is 488) and a single column: response.

Does that make sense? Or are we talking at cross purposes here?