How to find already exist customer id?

Question

How to find already exist customer id? pls tell me with example.

Satyapriya Nayak · Answer

Hi Magesh Try this... Untitled Page using System; using System.Collections; using System.Configuration; using System.Data; using System.Linq; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.HtmlControls; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Xml.Linq; using System.Data.SqlClient; namespace Know_user_id_exits { public partial class _Default : System.Web.UI.Page { string connStr = ConfigurationManager.ConnectionStrings[ConnectionString].ConnectionString; SqlDataAdapter sqlda; SqlCommand com; string str; DataSet ds; protected void btn_add_Click(object sender EventArgs e) { SqlConnection con = new SqlConnection(connStr); con.Open(); str = select * from student; sqlda = new SqlDataAdapter(str con); ds = new DataSet(); sqlda.Fill(ds student); int newid; newid = Convert.ToInt32(txtid.Text.ToString()); if (!checkIfUnique(newid)) { Response.Write(ID Already exists!); txtid.Focus(); return; } else { str = insert into student values ( + txtid.Text + ' + txtname.Text + '' + txtaddress.Text + '); com = new SqlCommand(str con); com.ExecuteNonQuery(); } con.Close(); } private bool checkIfUnique(int newid) { int oldid; foreach (DataRow r in ds.Tables[student].Rows) { oldid = Convert.ToInt32(r[sid]); if (oldid == newid) return false; } return true; } } } Thanks If this post helps you mark it as answer