why my code does not working to assign value into a textbox....

Question

1.00/5 (1 vote)

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what is the problem with these codes please help

C#

string conStr = ConfigurationManager.ConnectionStrings["CStringCRM"].ToString();
            DataTable dt = new DataTable();
            SqlDataReader dr = null;
            using(SqlConnection conn = new SqlConnection(conStr))
            {
                string sql = string.Format(@"SELECT top 1 ID FROM User order by ID desc"); 
                SqlCommand cmd = new SqlCommand();
                cmd.Connection = conn;
                cmd.CommandText = sql;
                cmd.CommandType = CommandType.Text;
                conn.Open();

                dr = cmd.ExecuteReader();

                dt.Load(dr);
                txtUID.Text = dr["ID"].ToString();
                conn.Close();
                cmd = null;

            }

Posted 31-Jul-15 1:16am

Altaful Haq

Updated 31-Jul-15 2:53am

v2

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2 solutions

Solution 1

Quote:
string sql = string.Format(@"SELECT top 1 ID FROM User order by ID desc");

Quote:
txtUID.Text = dr["UID"].ToString();

I see a mismatch...

Please note, the DataTable is useless in your code.

Posted 31-Jul-15 1:36am

CPallini

Comments

Altaful Haq 31-Jul-15 8:55am

Still Not Working with txtUID.Text = dr["ID"].ToString();

#CPallini

CPallini 31-Jul-15 8:58am

In order to ge better help you could report the exact error, if any ("not working" isn't much informative).

[no name] 31-Jul-15 9:07am

Just comment the line " dt.Load(dr);" in your code and make sure that you have records in your database to show up in text box.

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Richard Deeming · Accepted Answer · 2015-07-31T03:38:00

Solution 2

Here's a fixed version of your code:

C#

string conStr = ConfigurationManager.ConnectionStrings["CStringCRM"].ToString();

using (SqlConnection conn = new SqlConnection(conStr))
using (SqlCommand cmd = new SqlCommand(@"SELECT top 1 ID FROM User order by ID desc", conn))
{
    conn.Open();
    using (SqlDataReader dr = command.ExecuteReader(CommandBehavior.CloseConnection))
    {
        if (dr.Read())
        {
            txtUID.Text = Convert.ToString(dr["ID"]);
        }
    }
}

Consistent column name, as suggested by CPallini;
Removed the un-used DataTable and dt.Load(dr), as suggested by CPallini and CodeMaster_Noob;
Wrapped the SqlDataReader in a using block, and told it to close the connection when finished;
Added the required dr.Read() call before attempting to access values from the SqlDataReader;
Replaced dr["ID"].ToString() with Convert.ToString(dr["ID"]), in case the column value is null;

Posted 31-Jul-15 3:38am

Richard Deeming

Comments

Altaful Haq 3-Aug-15 0:28am

Thanks a lot Richard Deeming love your working with explanation...

Altaful Haq 3-Aug-15 0:49am

Can I increment that value by if yes than help me..

Richard Deeming 3-Aug-15 7:56am

Sorry, I don't understand your comment.

Altaful Haq 4-Aug-15 2:00am

in the above solution we get a value and assign it into the textbox e.g the value is 7 now i want to make that value 8... how would i do so.

Richard Deeming 4-Aug-15 7:20am

Assuming the ID column is an integer, something like this should work:

int id = Convert.ToInt32(dr["ID"]);
txtUID.Text = (id + 1).ToString();

Altaful Haq 4-Aug-15 8:39am

THANKS FOR HELPING

Altaful Haq 4-Aug-15 6:25am

i want to show the gridview data in a form can you help me with my code i try hard but it send the first record. because of dr.Read(); (some one told me that read() always started from the first record).

Richard Deeming 4-Aug-15 7:21am

Sounds like a completely different question.

Post a new question, and be sure to provide sufficient details about the code you've written and the problem you're having.