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Returning a single value from SQL Server query to a C# label

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Join Date: Jun 2009

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Returning a single value from SQL Server query to a C# label

Aug 19th, 2009

I am trying to populate a label using a T-Sql query to a SQL Server table upon a click event. I have the click event and linking to the SQL Server table working just fine. The process (below) returns "System.Windows.Forms.BindingSource" rather than any value from the table. My code is as follows.

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 C# Syntax (Toggle Plain Text) 
            string strCon = "Data Source=ITxxx;Initial Catalog=FDM;Integrated Security=True";
            // Mailed date
            string strSQLi = "select " +
                "Mailed_Dt " +
                "from [FDM].dbo.XREF_ProductTbl" +
                " where Product = " + " '" + cboxMailRespSelProgram.Text.ToString() + "'";
            SqlDataAdapter dataAdapterI = new SqlDataAdapter(strSQLi, strCon);
            SqlCommandBuilder commandBuilderI = new SqlCommandBuilder(dataAdapterI);
            DataTable tblProductI = new DataTable();
            BindingSource productIBindSource = new BindingSource();
            productIBindSource.DataSource = tblProductI;
            dataAdapterI.Fill(tblProductI);
            lblProductI.Text = "Mailed Date:  " + productIBindSource;
            string strCon = "Data Source=ITxxx;Initial Catalog=FDM;Integrated Security=True";
            // Mailed date
            string strSQLi = "select " +
                "Mailed_Dt " +
                "from [FDM].dbo.XREF_ProductTbl" +
                " where Product = " + " '" + cboxMailRespSelProgram.Text.ToString() + "'";
            SqlDataAdapter dataAdapterI = new SqlDataAdapter(strSQLi, strCon);
            SqlCommandBuilder commandBuilderI = new SqlCommandBuilder(dataAdapterI);
            DataTable tblProductI = new DataTable();
            BindingSource productIBindSource = new BindingSource();
            productIBindSource.DataSource = tblProductI;
            dataAdapterI.Fill(tblProductI);
            lblProductI.Text = "Mailed Date:  " + productIBindSource;

Your help will be greatly appreciated!

Last edited by John A; Aug 20th, 2009 at 10:27 pm. Reason: added code tags

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Re: Returning a single value from SQL Server query to a C# label

Aug 19th, 2009

>Returning a single value from SQL Server query to a C# label,
Use ExecuteScalar method of SqlCommand class.

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 ...
 object val=cmd.ExecuteScalar();
 ...
 ...
 object val=cmd.ExecuteScalar();
 ...

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Re: Returning a single value from SQL Server query to a C# label

Aug 20th, 2009

Using data adapters, command builders, etc is a little bit of overkill for the task at hand. As adatapost suggested you will want to use .ExecuteScalar() . Also keep in mind if the query may ever grow you will want to use a DataTable .

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      const string connStr = "Data Source=apex2006sql;Initial Catalog=Leather;Integrated Security=True;";
      const string query = "Select Password From UserTable (NOLOCK) Where UserName = @UserName";
      DataTable result = new DataTable();
      using (SqlConnection conn = new SqlConnection(connStr))
      {
        conn.Open();
        using (SqlCommand cmd = new SqlCommand(query, conn))
        {
          cmd.Parameters.Add("@UserName", SqlDbType.VarChar).Value = Username;
          using (SqlDataReader dr = cmd.ExecuteReader())
          {
            result.Load(dr);
            string textBoxStuff = Convert.ToString(result.Rows[0]["Column"]);
          }
        }
      }
      const string connStr = "Data Source=apex2006sql;Initial Catalog=Leather;Integrated Security=True;";
      const string query = "Select Password From UserTable (NOLOCK) Where UserName = @UserName";
      DataTable result = new DataTable();
      using (SqlConnection conn = new SqlConnection(connStr))
      {
        conn.Open();
        using (SqlCommand cmd = new SqlCommand(query, conn))
        {
          cmd.Parameters.Add("@UserName", SqlDbType.VarChar).Value = Username;
          using (SqlDataReader dr = cmd.ExecuteReader())
          {
            result.Load(dr);
            string textBoxStuff = Convert.ToString(result.Rows[0]["Column"]);
          }
        }
      }