From a8f57cbaa9ee01ce4e84f671c9f7bd66203f065e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E7=8E=8B=E5=B8=85?= <3309605189@qq.com>
Date: Wed, 25 May 2022 00:40:31 +0800
Subject: [PATCH] =?UTF-8?q?=E7=BB=83=E4=B9=A0?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../\347\273\203\344\271\2403.md"             | 37 +++++++++++++++++++
 1 file changed, 37 insertions(+)
 create mode 100644 "\347\216\213\345\270\205/\347\273\203\344\271\2403.md"

diff --git "a/\347\216\213\345\270\205/\347\273\203\344\271\2403.md" "b/\347\216\213\345\270\205/\347\273\203\344\271\2403.md"
new file mode 100644
index 0000000..dea4c4b
--- /dev/null
+++ "b/\347\216\213\345\270\205/\347\273\203\344\271\2403.md"
@@ -0,0 +1,37 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Web;
+using System.Web.UI;
+using System.Web.UI.WebControls;
+
+namespace WebApplication1
+{
+    public partial class WebForm1 : System.Web.UI.Page
+    {
+        protected void Page_Load(object sender, EventArgs e)
+        {
+            if (!Page.IsPostBack) {
+                SqlDataSource1.SelectCommand = "select * from city where type=1 ";
+                SqlDataSource2.SelectCommand = "select * from city where type=2 and pid=2";
+                SqlDataSource3.SelectCommand = "select * from city where type=3 and pid in (select id from city where type = 2 and pid = 2)";
+            }
+
+        }
+    
+        protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
+        {
+        
+            SqlDataSource2.SelectCommand = "select * from city where type=2 and pid=" + DropDownList1.SelectedValue;
+            
+            SqlDataSource3.SelectCommand = "select * from city where type=3 and pid in "(select id from city where type = 2 and pid = " + DropDownList1.SelectedValue+")";
+        }
+    
+        protected void DropDownList2_SelectedIndexChanged(object sender, EventArgs e)
+        {
+        
+            SqlDataSource3.SelectCommand = "select * from city where type=3 and pid =" + DropDownList2.SelectedValue;
+            
+        }
+    }
+}
\ No newline at end of file
-- 
Gitee