检查数据库上已经存在的记录. [英] put a check on the record already exits on the database.

问题描述

我正在数据库表中输入要检查的记录.如果再次输入数据库中已经存在的记录..我想在customer.aspx页面上显示错误..我该如何放置检查

i am entering records in the database table i want to make a check. if the record that is already exits in the database is entered again.. i want to show a error on customer.aspx page.. how can i put a check

推荐答案

您可以在后面的代码中尝试...尝试此代码..

You can try that in code behind...Try this code its work..

 protected void Page_Load(object sender, EventArgs e)
        {
            
               if (!string.IsNullOrEmpty(TextBox1.Text))
            {
                SqlConnection con;
                SqlCommand cmd;
                string constr = ConfigurationManager.ConnectionStrings["SomeDataBase"].ToString();
                con = new SqlConnection(constr);

                cmd = new SqlCommand("Select * from Thi where Username=@Username", con);
                con.Open();
                cmd.Parameters.AddWithValue("@Username", TextBox1.Text);
                SqlDataReader dr = cmd.ExecuteReader();
                
                if (dr.HasRows)
                {
                    
                    checkusername.Visible = true;
                    imgstatus.ImageUrl = "Images/NotAvailable.jpg";
                    Label3.Text = "UserName Already Taken";
                    if (Label3.Text == "UserName Already Taken")
                    {
                        TextBox1.Text = " ";
                    }
                    System.Threading.Thread.Sleep(2000);
                }
                else
                {
                    checkusername.Visible = true;
                    imgstatus.ImageUrl = "Images/Icon_Available.gif";
                    Label3.Text = "UserName Available";
                    System.Threading.Thread.Sleep(1000);
                    con.Close();
                }

            }

            else
            {
                checkusername.Visible = false;
            }
}

编码愉快.

Happy coding.

这篇关于检查数据库上已经存在的记录.的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！