retrieving radioButton value from SQL Server using C#

Try executing the command

genderval = (Boolean)gendercmnd.ExecuteScalar();

Also note that your query should be parameterized. Here is a complete example (using SqlConnection but if you replace the Sql classes with your provider classes it should work for you)

bool genderval;

using (SqlConnection conn = new SqlConnection("youeConnStr"))
{
    conn.Open();
    using (SqlCommand cmd = new SqlCommand("SELECT Gender FROM Std_info WHERE Id = @id", conn))
    {
        int id = Convert.ToInt32(TextBox1.Text);
        cmd.Parameters.Add(new SqlParameter("@id", id));
        genderval = (bool)cmd.ExecuteScalar();
    }
}

Looks as though you haven't actually queried the database yet, but are attempting to convert the actual command rather than the results gathered.

I'm not sure if the same works for SQL Server Compact but you need to either ExecuteNonScalar or Execute the command itself, retrieve the results and then run your comparison on that.

Are you executing the command against the db and getting results? as that code doesn't look like it is doing it. I think you need to call ExecuteScalar() on the sqlcecommand.

What you're trying to do is to get a result from the SQL server, and cast it as a boolean.

What you're actually doing is trying to convert your SQL command into a boolean.

What you need to do is actually open the connection to the SQL server and execute your query. But it's a bit more complex than that...

if (con.State != ConnectionState.Open)
   con.Open();

Boolean genderval = false;
SqlCeCommand gendercmnd = new SqlCeCommand(@"SELECT Gender FROM Std_info WHERE Std_id='" + TextBox1.Text + "'", con);

gendercmnd.Connection.Open(); // Open the connection using the gendercmd string.
sqlReader = gendercmnd.ExecuteReader(); // Execute the read, which returns an SqlCEDataReader object that we can use to access the data. 


genderval = Convert.ToBoolean(gendercmndResult);
            if (genderval == true)
                Convert.ToBoolean(radioButton1.Checked);
            else
                Convert.ToBoolean(radioButton2.Checked);  
con.Close();

Now we need to take the value from the reader, and cast that as a boolean.

if (con.State != ConnectionState.Open)
   con.Open();

Boolean genderval = false;
String gendercmndResult = null;
SqlCeCommand gendercmnd = new SqlCeCommand(@"SELECT Gender FROM Std_info WHERE Std_id='" + TextBox1.Text + "'", con);

gendercmnd.Connection.Open(); // Open the connection using the gendercmd string.
sqlReader = gendercmnd.ExecuteReader(); returns an SqlCEDataReader object that we can use to access the data.

while (sqlReader.Read(){ //While the reader is reading...
    gendercmndResult = (sqlReader.GetString(0)); //Assign the returned value from the SQL server to a string called gendercmndResult
}


genderval = Convert.ToBoolean(gendercmndResult); //Now we can cast the string as a bool
            if (genderval == true)
                Convert.ToBoolean(radioButton1.Checked);
            else
                Convert.ToBoolean(radioButton2.Checked);  
con.Close();