Set SelectCommand : DataGrid : Database C# Source Code

    
 

using System;
using System.Diagnostics;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Data.SqlClient;

public class Form1 : System.Windows.Forms.Form {
    private System.Windows.Forms.Label label1;
    private System.Windows.Forms.TextBox txtStateWanted;
    private System.Windows.Forms.Button btnFind;
    private System.Windows.Forms.DataGrid dataGrid1;
    public Form1() {
        this.label1 = new System.Windows.Forms.Label();
        this.txtStateWanted = new System.Windows.Forms.TextBox();
        this.btnFind = new System.Windows.Forms.Button();
        this.dataGrid1 = new System.Windows.Forms.DataGrid();
        ((System.ComponentModel.ISupportInitialize)(this.dataGrid1)).BeginInit();
        this.SuspendLayout();

        this.label1.Location = new System.Drawing.Point(62, 241);
        this.label1.Size = new System.Drawing.Size(32, 23);
        this.label1.Text = "State";

        this.txtStateWanted.Location = new System.Drawing.Point(102, 241);
        this.txtStateWanted.Size = new System.Drawing.Size(64, 20);
        this.txtStateWanted.Text = "CA";

        this.btnFind.Location = new System.Drawing.Point(206, 241);
        this.btnFind.Text = "Fill";
        this.btnFind.Click += new System.EventHandler(this.btnFind_Click);

        this.dataGrid1.DataMember = "";
        this.dataGrid1.HeaderForeColor = System.Drawing.SystemColors.ControlText;
        this.dataGrid1.Location = new System.Drawing.Point(6, 9);
        this.dataGrid1.Size = new System.Drawing.Size(280, 224);

        this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
        this.ClientSize = new System.Drawing.Size(292, 273);
        this.Controls.AddRange(new System.Windows.Forms.Control[] {
                                                                          this.label1,
                                                                          this.txtStateWanted,
                                                                          this.btnFind,
                                                                          this.dataGrid1});
        ((System.ComponentModel.ISupportInitialize)(this.dataGrid1)).EndInit();
        this.ResumeLayout(false);

    }
    [STAThread]
    static void Main() {
        Application.Run(new Form1());
    }

    private void btnFind_Click(object sender, System.EventArgs e) {
        try {
            DataSet ds = new DataSet();
            SqlDataAdapter da = new SqlDataAdapter("SELECT pubid, pubname, city, state FROM publishers where state = @State", "data source=.;database=biblio;uid=admin;pwd=pw");

            da.SelectCommand.Parameters.Add("@State", txtStateWanted.Text);
            da.Fill(ds, "PublishersIn" + txtStateWanted.Text);
            dataGrid1.DataSource = ds.Tables[0];
        } catch (SqlException sex) {
            Debug.WriteLine(sex.ToString());
        }
    }
}