利用AJAX验证输入的用户名在sqlserver数据库中是否已经存在

Myth丶恋晨 2021-09-16 23:18 393阅读 0赞

![20181110215706675.png][]     ![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70][]

HtmlPage.html：

<html>
    <head>
        <meta charset="utf-8" />
        <title></title>
        <script type="text/javascript">
            var xmlHttp;
            function Validation() {
    
                if (window.XMLHttpRequest) {
                    xmlHttp = new XMLHttpRequest();
                } else {
                    xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
                }
                var name = document.getElementById("Text1");
                xmlHttp.open("Get", "Default2.aspx?name=" + name.value);
                xmlHttp.onreadystatechange= onmessageBack;
                xmlHttp.send(null);
            }
    
            function onmessageBack(){
                if (xmlHttp.readyState == 4 && xmlHttp.status == 200) {
                    document.getElementById("result").innerHTML = xmlHttp.responseText;
                }
            }
        </script>
    </head>
    <body>
        <form id="form1" runat="server">
            请在下面的文本框中输入用户名，进行检验<br />
            用户名：
            <input id="Text1" type="text" onblur="Validation()" /><br />
            <div id="result"></div>
    
        </form>
    </body>
    </html>

Default2.aspx.cs：

private string myConnStr = ConfigurationManager.ConnectionStrings["SQL"].ConnectionString;
        protected void Page_Load(object sender, EventArgs e)
        {
            Response.Expires = -1;
            string name = this.Request.QueryString["name"];
    
            string mydr;
            SqlConnection myConn = new SqlConnection(myConnStr);
            string sql = "SELECT UserName from Users WHERE UserName=";
            sql = sql + "'" + name  + "'";
            SqlCommand sqlCommand = new SqlCommand(sql, myConn);
            try
            {
                myConn.Open();
                if (name != "")
                {
                    if (sqlCommand.ExecuteScalar() != null)
                    {
                        mydr = sqlCommand.ExecuteScalar().ToString();
                        Response.Write("该用户名已被注册，请返回重新注册！");
                        Response.End();
                    }
                    else
                    {
                        Response.Write("该用户名可用。");
                        Response.End();
                    }
                }
                else
                {
                    Response.Write("请输入用户名！");
                    Response.End();
                }
            }
            catch (SqlException se)
            {
    
                Response.Write(se.Message + "<br>");
                Response.End();
            }
            finally
            {
                myConn.Close();
            }
        }

Web.config:

![20181110221931644.png][]![20181110222101615.png][]

![20181110222121779.png][]

[20181110215706675.png]: https://img-blog.csdnimg.cn/20181110215706675.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70]: /images/20210725/a902924710d640738bbeb534222ff186.png
[20181110221931644.png]: https://img-blog.csdnimg.cn/20181110221931644.png
[20181110222101615.png]: /images/20210725/a078fbbe44a24cf39b24979f13e2055b.png
[20181110222121779.png]: /images/20210725/fdb2718272ae4c6ebcbfec832556787b.png