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The variable 'sql' is assigned but its value is never used

Posted on 2009-05-13
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Last Modified: 2013-12-17
Good afternoon expert,

Getting error messages in VS 2005
The variable 'sql' is assigned but its value is never used
The variable 'connStringl' is assigned but its value is never used

But they are used at
dsToolkit.SelectCommand = sql;
and
dsToolkit.ConnectionString = connString;

So why does th compiler complain?

Allen



using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
 
public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        //Default SQL statement which will be executed when no search conditions were entered
        String sql = "SELECT tblSecurity.Username, tblSecurity.First_Name, tblSecurity.Last_Name, tblSecurity.Company_number FROM tblSecurity";
        //Connection string - @@DBName will be replaced by the server name selected from the
        //Environment dropdown
        String connString = "DATA SOURCE = Labsdirvg600;Initial Catalog=TimeEntry;User ID=Labswirvg600;Password=Kling0n1";
        //A boolean field which is used to add a WHERE clause to the SQL statement
        //Boolean whereClauseAdded = false;
 
        //Connection string is formed here. cboEnvironment.SelectedItem.Value will return
        //the selected environment.
        //connString = connString.Replace("@@DBName", cboEnvironment.SelectedItem.Value);
    }
 
    protected void btnSubmit_Click(object sender, EventArgs e)
    {
        if (query.Checked)
            sql = "SELECT * from tblSecurity where Username Like '%sm'";
        if (query.Checked)
 
            sql = "SELECT * from tblSecurity where Username Like '%jo'";
 
 
        //Set the connection string of the SQLDataSource here
        dsToolkit.ConnectionString = connString;
 
        //Atleast one search criteria must be entered by the user if a WHERE clause needs to be
        //added
 
        //Now, the dynamically created SQL statement needs to be assigned to the SQL Data source
        dsToolkit.SelectCommand = sql;
 
        //Finally, refresh the Grid, which will cause the data source to execute the above created
        //SQL and show the results in the grid
        grdPayroll.DataBind();
    }
 
}

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Question by:9apit
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3 Comments
 
LVL 143

Expert Comment

by:Guy Hengel [angelIII / a3]
ID: 24379389
change:
 protected void btnSubmit_Click(object sender, EventArgs e)
    {
        sql = string.empty;
        if (query.Checked)
            sql = "SELECT * from tblSecurity where Username Like '%sm'";
        if (query.Checked)
 
            sql = "SELECT * from tblSecurity where Username Like '%jo'";
 

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Author Comment

by:9apit
ID: 24379526
Angelll,

Installed code now get
Warning      2      The variable 'sql' is assigned but its value is never used      C:\Inetpub\wwwroot\TK090514\Default.aspx.cs      16      16      C:\...\TK090514\
Warning      3      The variable 'connString' is assigned but its value is never used      C:\Inetpub\wwwroot\TK090514\Default.aspx.cs      19      16      C:\...\TK090514\
Error      4      The name 'sql' does not exist in the current context      C:\Inetpub\wwwroot\TK090514\Default.aspx.cs      31      9      C:\...\TK090514\
Error      5      'string' does not contain a definition for 'empty'      C:\Inetpub\wwwroot\TK090514\Default.aspx.cs      31      22      C:\...\TK090514\
Error      6      The name 'query' does not exist in the current context      C:\Inetpub\wwwroot\TK090514\Default.aspx.cs      32      13      C:\...\TK090514\
Error      7      The name 'sql' does not exist in the current context      C:\Inetpub\wwwroot\TK090514\Default.aspx.cs      33      13      C:\...\TK090514\
Error      8      The name 'query' does not exist in the current context      C:\Inetpub\wwwroot\TK090514\Default.aspx.cs      34      13      C:\...\TK090514\
Error      9      The name 'sql' does not exist in the current context      C:\Inetpub\wwwroot\TK090514\Default.aspx.cs      36      13      C:\...\TK090514\
Error      10      The name 'connString' does not exist in the current context      C:\Inetpub\wwwroot\TK090514\Default.aspx.cs      42      38      C:\...\TK090514\
Error      11      The name 'sql' does not exist in the current context      C:\Inetpub\wwwroot\TK090514\Default.aspx.cs      52      35      C:\...\TK090514\
0
 
LVL 143

Accepted Solution

by:
Guy Hengel [angelIII / a3] earned 500 total points
ID: 24379560
sorry, I got the error message wrong.

the problem is that you define sql in the page load, instead of the class level
using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
 
public partial class _Default : System.Web.UI.Page
{
    String sql = String.Empty; 
 
    protected void Page_Load(object sender, EventArgs e)
    {
        //Default SQL statement which will be executed when no search conditions were entered
        sql = "SELECT tblSecurity.Username, tblSecurity.First_Name, tblSecurity.Last_Name, tblSecurity.Company_number FROM tblSecurity";
        //Connection string - @@DBName will be replaced by the server name selected from the
        //Environment dropdown
        String connString = "DATA SOURCE = Labsdirvg600;Initial Catalog=TimeEntry;User ID=Labswirvg600;Password=Kling0n1";
        //A boolean field which is used to add a WHERE clause to the SQL statement
        //Boolean whereClauseAdded = false;
 
        //Connection string is formed here. cboEnvironment.SelectedItem.Value will return
        //the selected environment.
        //connString = connString.Replace("@@DBName", cboEnvironment.SelectedItem.Value);
    }
 
    protected void btnSubmit_Click(object sender, EventArgs e)
    {
        if (query.Checked)
            sql = "SELECT * from tblSecurity where Username Like '%sm'";
        if (query.Checked)
 
            sql = "SELECT * from tblSecurity where Username Like '%jo'";
 
 
        //Set the connection string of the SQLDataSource here
        dsToolkit.ConnectionString = connString;
 
        //Atleast one search criteria must be entered by the user if a WHERE clause needs to be
        //added
 
        //Now, the dynamically created SQL statement needs to be assigned to the SQL Data source
        dsToolkit.SelectCommand = sql;
 
        //Finally, refresh the Grid, which will cause the data source to execute the above created
        //SQL and show the results in the grid
        grdPayroll.DataBind();
    }
 
}

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