Asp.net如何使用验证控制代码

Question

实际上我正在设计我的网页，因为我输入了图书 ID 和
书名。键入，然后单击按钮 图书可用 转到另一个页面，然后不可用 显示错误消息 图书不可用 我的项目（图书馆管理系统） Asp.net sql server 如何验证页面以及如何设置验证控制以及如何设置验证控制代码...向我发送完整详细信息

My code
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;


public partial class Bookcheck : System.Web.UI.Page
{
      public Int64 Sid;
    protected void Page_Load(object sender, EventArgs e)
    {
        string Id;
        Id = Request.QueryString.Get(0);

    if (!(IsPostBack == true))
    {
        if (Request.QueryString.Get(1) == "G")
        {
            Sid = Convert.ToInt64(Id);
            if (PopulatedRecord (Sid ) == false)
            {

            }
        }
    }
}
private Boolean PopulatedRecord(Int64 Id)
{
    DataSet DS;
    DS = new DataSet();
    SqlCommand cmd = new SqlCommand();
    SqlDataAdapter da = new SqlDataAdapter();
    SqlConnection Cnn = new SqlConnection();
    string connectionstring;
    connectionstring = @"Datasource=DEVI\SQLEXPRESS;Intial catalog=librarymanagement;Integrated Security=SSPI";
    Cnn.ConnectionString = connectionstring;
    if (Cnn.State != ConnectionState.Open)
        Cnn.Open();
    cmd.Connection = Cnn;
    cmd.CommandType = CommandType.StoredProcedure;
    cmd.CommandText = "usbinsertdatainto";
    cmd.Parameters.Clear();
    cmd.Parameters.AddWithValue("@bookId",txtid );
    da.SelectCommand = cmd;
    try
    {
        da.Fill(DS);
    }
    catch (Exception ex)
    {
        throw new ApplicationException(
            "!!! An Error Occured While Update Record In Dtl_SecurityCapital_Upload." + ex.Message);
        lblerror.Visible = true;
        lblerror.Text = "!!! An Error Occured While " + ex.Message.ToString();
        return false;
    }
    if (DS.Tables[0].Rows.Count > 0)
    {
        txtid.Text = DS.Tables[0].Rows[0]["bookId"].ToString();
        txtnb.Text = DS.Tables[0].Rows[0]["Nameofthebook"].ToString();
    }
    cmd.Dispose();
    Cnn.Close();
    Cnn.Dispose();
    return true;
}


}
        protected void  Button2_Click(object sender, EventArgs e)
         {
        if(Page.IsValid )
        {
        Response.Redirect ("issueofbook.aspx?bookid="+txtid.Text  

                                             +"&Nameofthebook="+txtnb.Text);
          }
      }
    }      

                   Error
                               Line 59:             throw new ApplicationException(
                               Line 60:                 "!!! An Error Occured While  
                                                      Update                              

                               Record In Dtl_SecurityCapital_Upload." + ex.Message);
                                Line 61:             lblerror.Visible = true;
                                   Line 62:             lblerror.Text = "!!! An Error 
                                                Occured While " +                          
                                                             ex.Message.ToString();

第 63 行：返回 false；

Answer 1

亲爱的，
使用 RequiredFieldValidator (ASP .NET 控件）用于检查 TextBox 是否为空。
或者
使用 JavaScript 检查文本框是否为空

标记：

<asp:TextBox ID="txtNo" runat="server" />
<asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server"  ErrorMessage="No Required " ControlToValidate="txtNo" />
<asp:TextBox ID="txtName" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="RequiredFieldValidator2" runat="server" ErrorMessage="Name Required " ControlToValidate="txtName" />
<asp:Button ID="Button1" runat="server" onclick="Button1_Click" Text="Button" />

按钮单击事件：

protected void Button1_Click(object sender, EventArgs e)
{
    if (Page.IsValid)
    {
        Response.Redirect("~/Newpage.aspx?no=" + txtNo.Text + "&name=" + txtName.Text); 
    }
}