自定义验证控件验证用户名是否被注册？

[cqnuzjj]

运行的时候老是提示User附近有语法错误：

<li>用户名：<asp:TextBox ID="txtName" runat="server" ></asp:TextBox>
    <asp:CustomValidator ID="csvCheckuser" runat="server" 
        ControlToValidate="txtName" ErrorMessage="该用户名已被注册！" 
        onservervalidate="csvCheckuser_ServerValidate">该用户名已被注册！</asp:CustomValidator>
</li>

验证代码（C#）：

protected void csvCheckuser_ServerValidate(object source, ServerValidateEventArgs args)
    {
        string sConnectionString = ConfigurationManager.ConnectionStrings["decoraconn"].ToString();
        SqlConnection conn = new SqlConnection(sConnectionString);
        conn.Open();
        SqlCommand cmd = new SqlCommand("select count(*) from User where username='"+this.txtName.Text.ToString()+"'",conn);
        int count = Convert.ToInt32(cmd.ExecuteScalar());
        conn.Close();
        if (count>0)
            {
             args.IsValid = false;
             }
           else
            {
             args.IsValid = true;
            }
    }

注：表名是User，用户名字段是username

[melon23]

看不出有什么问题

select count(*) from User where username=...
放到sql上面试试

或者用参数试试
select count(*) from User where username=@username

[yanrabbit163]

User是关键字,最好不要用这种关键字做表名,如果一定要用,就把User用[]括起来