为什么我在执行 if。。else的时候重新执行了两遍？

能帮我看看原因吗？
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;
using WSE_Booking.BLL;
using WSE_Booking.Model;public partial class M_预约课程5 : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (Session["M_Uname"] == null)
        { Response.Redirect("WSE_Login.aspx"); }
        else
        {
            Label1.Text = "";
SqlDataSource1.SelectCommand = "select * from 课程信息表 where C_Time>'" + DateTime.Now + "' and C_ID in(select C_ID from(select C_ID,COUNT(C_ID) as Times from 定课表 group by C_ID having COUNT(C_ID)<C_Num)t) or C_Time>'" + DateTime.Now + "' and C_ID not in(select C_ID from 定课表) order by C_ID desc";
        }    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        DateTime a = DateTime.Now;
        if (DropDownList1.SelectedItem.Value.ToString() == "Encounter")
            SqlDataSource1.SelectCommand = "select * from 课程信息表 where C_Time>'" + a + "' and C_Style='Encounter' and C_ID in(select C_ID from(select C_ID,COUNT(C_ID) as Times from 定课表 group by C_ID having COUNT(C_ID)<4)t) or C_Style='Encounter' and C_Time>'" + DateTime.Now + "' and C_ID not in(select C_ID from 定课表) order by C_ID desc";
        else if (DropDownList1.SelectedItem.Value.ToString() == "Complementary Class")
            SqlDataSource1.SelectCommand = "select * from 课程信息表 where C_Time>'" + a + "' and C_Style='Complementary Class' and C_ID in(select C_ID from(select C_ID,COUNT(C_ID) as Times from 定课表 group by C_ID having COUNT(C_ID)<8)t) or C_Style='Complementary Class' and C_Time>'" + DateTime.Now + "' and C_ID not in(select C_ID from 定课表) order by C_ID desc";
        else if (DropDownList1.SelectedItem.Value.ToString() == "Social Club")
            SqlDataSource1.SelectCommand = "select * from 课程信息表 where C_Time>'" + a + "' and C_Style='Social Club' and C_ID in(select C_ID from(select C_ID,COUNT(C_ID) as Times from 定课表 group by C_ID having COUNT(C_ID)<12)t) or C_Style='Social Club' and C_Time>'" + DateTime.Now + "' and C_ID not in(select C_ID from 定课表)  order by C_ID desc";
        else
            SqlDataSource1.SelectCommand = "select * from 课程信息表 where C_Time>'" + a + "' and C_ID in(select C_ID from(select C_ID,COUNT(C_ID) as Times from 定课表 group by C_ID having COUNT(C_ID)<C_Num)t) or C_Time>'" + DateTime.Now + "' and C_ID not in(select C_ID from 定课表) order by C_ID desc";
        GridView1.DataBind();    }
    protected void Button3_Click(object sender, EventArgs e)
    {
        for (int i = 0; i < TextBox3.Text.Length; i++)//是否录入的编号为数字
        {
            if (char.IsNumber(TextBox3.Text[i]) != true)
            {
                Label1.Text = "您输入的编号错误，请重新输入!! ";            }
            else
            {
                Label1.Text = " ";

        if (TextBox3.Text != "" && TextBox4.Text != "" && new 课程信息Bll().Exists2(Convert.ToInt32(TextBox3.Text)) == true)//用户名，编号不能为空，且该课程编号要存在
        {
            定课表 a = new 定课表();
            a.C_ID = Convert.ToInt32(TextBox3.Text);
            a.S_Uname = TextBox4.Text;
            string strCon = "Data Source=53E2ED31D85A42C\\SQLEXPRESS;Initial Catalog=wall steet English Booking System;Integrated Security=True";
            SqlConnection cn = new SqlConnection();
            cn.ConnectionString = strCon;
            cn.Open();            SqlCommand cmd = new SqlCommand();
            cmd.CommandText = "SELECT C_Style FROM 课程信息表 WHERE C_ID='" + TextBox3.Text + "'";
            cmd.Connection = cn;            a.C_Style = Convert.ToString(cmd.ExecuteScalar());
            SqlCommand cmd1 = new SqlCommand();
            cmd.CommandText = "SELECT C_Time FROM 课程信息表 WHERE C_ID='" + TextBox3.Text + "'";
            cmd.Connection = cn;            a.C_Time = Convert.ToDateTime(cmd.ExecuteScalar());            SqlCommand cmd2 = new SqlCommand();
            cmd.CommandText = "SELECT T_Name FROM 课程信息表 WHERE C_ID='" + TextBox3.Text + "'";
            cmd.Connection = cn;            a.T_Name = Convert.ToString(cmd.ExecuteScalar());
            SqlCommand cmd5 = new SqlCommand();            cmd.CommandText = "SELECT C_Hours FROM 课程信息表 WHERE C_ID='" + TextBox3.Text + "'";
            cmd.Connection = cn;            a.C_Hours = Convert.ToString(cmd.ExecuteScalar());
            cn.Close();
            if (new 学员信息Bll().Exists(TextBox4.Text) == true)//判断是否存在该用户
            {                if (new 定课信息Bll().Exists(Convert.ToInt32(TextBox3.Text)) == false)//验证课程编号在定课表中是否存在，如果不出在课直接添加成功！
                {
                    new 定课信息Bll().Add(a);                    Label1.Text = "课程预约成功！！！";                }

                else if (new 定课信息Bll().Exists2(TextBox4.Text) == true)//判断是否存在该学员同一个课程的信息，如果不存在，预约成功！
                {
                    string strCon2 = "Data Source=53E2ED31D85A42C\\SQLEXPRESS;Initial Catalog=wall steet English Booking System;Integrated Security=True";
                    SqlConnection cn2 = new SqlConnection();
                    cn2.ConnectionString = strCon2;
                    cn2.Open();                    SqlCommand cmd4 = new SqlCommand();
                    cmd4.CommandText = "SELECT C_ID FROM 定课表 WHERE S_Uname='" + TextBox4.Text + "' AND C_ID='" + TextBox3.Text + "'";
                    cmd4.Connection = cn2;
                    int c;
                    c = Convert.ToInt32(cmd4.ExecuteScalar());                    if (c == 0)
                    {
                        new 定课信息Bll().Add(a);                        Label1.Text = "课程预约成功！！！";                    }
                    else
                    {                        Label1.Text = "定课失败，该学员已经预约过该课程，无法重复预约！";
                    }
                    cn2.Close();
                }
                else if (new 定课信息Bll().Exists(Convert.ToInt32(TextBox3.Text)) == true)//判断是否存在该学员同一个课程的信息，如果不存在，预约成功！
                {
                    string strCon3 = "Data Source=53E2ED31D85A42C\\SQLEXPRESS;Initial Catalog=wall steet English Booking System;Integrated Security=True";
                    SqlConnection cn3 = new SqlConnection();
                    cn3.ConnectionString = strCon3;
                    cn3.Open();                    SqlCommand cmd3 = new SqlCommand();
                    cmd3.CommandText = "SELECT S_Uname FROM 定课表 WHERE S_Uname='" + TextBox4.Text + "' AND C_ID='" + TextBox3.Text + "'";
                    cmd3.Connection = cn3;
                    string d;
                    d = Convert.ToString(cmd3.ExecuteScalar());
                    cn3.Close();
                    if (d == null || d.Equals(""))
                    {
                        new 定课信息Bll().Add(a);                        Label1.Text = "课程预约成功！！！";
                    }
                    else
                    {
                        Label1.Text = "定课失败，该学员已经预约过该课程，无法重复预约！";
                    }
                }            }
            else
            {
                Label1.Text = "不存在该用户，请重新输入！！！";            }        }
        else
        {
            Label1.Text = "您没有输入课程编号或用户名或录入的信息有误，请重新录入！！！";
        }      }
    }
    }
}我在录入信息后，点击添加后，该程序从if开始执行，执行后，又重新从if开始执行了一遍，这是为什么？能帮我解决下吗？

解决方案 »

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1.调试
2.检查代码吧，执行顺序  if (DropDownList1.SelectedItem.Value.ToString() == "Encounter")
  明显的｛｝都没有
Page_Load重复执行吗？ if (!IsPostBack)
{
   if ... else ...
}
if(!ispostback)
{

}
  if (!Page.IsPostBack)
        {少了这个
for (int i = 0; i < TextBox3.Text.Length; i++)//是否录入的编号为数字
  {
  if (char.IsNumber(TextBox3.Text[i]) != true)
  {
  Label1.Text = "您输入的编号错误，请重新输入!! ";  }}
我解决了，是应为 for (int i = 0; i < TextBox3.Text.Length; i++)的问题，我要是输入两位数它就自动执行两遍。。我错了对不起大家
if(!ispostback)
{
} 这个不能少、
if (!IsPostBack){}吧你的if放到这个里面
protected void Page_Load(object sender, EventArgs e)
  {
     if (!IsPostBack){//用于判断是提交还是刷新
              .....................添加您自己代码
}
}

为什么我在执行 if。。else的时候 重新执行了两遍？

解决方案 »

为什么我在执行 if。。else的时候重新执行了两遍？