Question

Consider the following code:

SqlConnection conn = new SqlConnection(@"connection string");

SqlCommand ourCommand = new SqlCommand(String.Format(
    @"SELECT Field1,Field2,Field3 FROM Tbl WHERE Field1 LIKE '@FL1'"), conn);
ourCommand.CommandTimeout = 6000;

ourCommand.Parameters.AddWithValue("@FL1", TextBox1.Text);

SqlDataAdapter adapter = new SqlDataAdapter(ourCommand);
DataTable dt = new DataTable();

conn.Open();
adapter.Fill(dt);
GridView1.DataSource = dt;

GridView1.DataBind();

The problem is that datatable is empty – which means the command either was not executed or incorrect query was generated. What am I missing? Connection and query are valid. The command without parameter also works. Database engine is SQL Server 2008 R2

Answer 1

You’ve put the parameter name in quotes, so it’s being treated as a value, not as a parameter. Try this instead:

"SELECT Field1,Field2,Field3 FROM Tbl WHERE Field1 LIKE @FL1"

(I’d actually expect your existing code to throw an exception given that you’re supplying more parameters than are in the SQL…)

As noted in comments, you don’t need the string.Format either.