From 968f848b662e4798456a4318d5db0f2dbacae3ff Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E8=93=9D=E6=96=87=E9=BE=99?= <1617162119@qq.com>
Date: Tue, 24 May 2022 14:18:08 +0000
Subject: [PATCH 1/2] =?UTF-8?q?=E6=96=B0=E5=BB=BA=2049=E8=93=9D=E6=96=87?=
 =?UTF-8?q?=E9=BE=99?=
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Gitee


From 77a88cfc5b2484cd7940cba45a96e12bc7f0bed0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E8=93=9D=E6=96=87=E9=BE=99?= <1617162119@qq.com>
Date: Tue, 24 May 2022 14:32:05 +0000
Subject: [PATCH 2/2] =?UTF-8?q?=E7=9C=81=E5=B8=82=E5=8E=BF?=
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 ...0\347\234\201\345\270\202\345\216\2771.md" | 72 +++++++++++++++++++
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 create mode 100644 "49\350\223\235\346\226\207\351\276\231/\347\254\254\344\270\211\347\253\240\347\234\201\345\270\202\345\216\2771.md"

diff --git "a/49\350\223\235\346\226\207\351\276\231/\347\254\254\344\270\211\347\253\240\347\234\201\345\270\202\345\216\2771.md" "b/49\350\223\235\346\226\207\351\276\231/\347\254\254\344\270\211\347\253\240\347\234\201\345\270\202\345\216\2771.md"
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+++ "b/49\350\223\235\346\226\207\351\276\231/\347\254\254\344\270\211\347\253\240\347\234\201\345\270\202\345\216\2771.md"
@@ -0,0 +1,72 @@
+```asp
+using System.Web.UI.WebControls;
+
+namespace Demo1
+{
+    public partial class Province : System.Web.UI.Page
+    {
+        protected void Page_Load(object sender, EventArgs e)
+        {
+            if (!IsPostBack) { 
+            //SelectCommand：设置数据源的select命令
+            SqlDataSource1.SelectCommand = "select id,cityName from city where type=1";
+```
+
+
+
+```asp
+        //初始化城市信息，父级id为2（北京市下的城市信息）
+        SqlDataSource2.SelectCommand = "select * from city where type=2 and pid=" + 2;
+
+       //初始化区县信息
+       SqlDataSource3.SelectCommand = "select * from city where type=3 and pid=(select top 1 id from city where pid=2)" ;
+        }
+    }
+
+    /// <summary>
+    /// 省份下拉框文本发生改变时执行的子程序
+    /// </summary>
+    /// <param name="sender"></param>
+    /// <param name="e"></param>
+    protected void ddl_Province_TextChanged(object sender, EventArgs e)
+    {
+        //ddl_Province.SelectedValue获取省份下拉框的选中值，也就是选择的省份的id
+        SqlDataSource2.SelectCommand = "select * from city where type=2 and pid="+ddl_Province.SelectedValue;
+    }
+
+    protected void ddl_City_TextChanged(object sender, EventArgs e)
+    {
+        SqlDataSource3.SelectCommand = "select * from city where type=3 and pid="+ddl_City.SelectedValue;
+    }
+
+    protected void SqlDataSource1_Selecting(object sender, SqlDataSourceSelectingEventArgs e)
+    {
+
+    }
+
+    protected void SqlDataSource3_Selecting(object sender, SqlDataSourceSelectingEventArgs e)
+    {
+
+    }
+}
+```
+
+
+
+
+
+
+
+
+ <div>
+            省份：<asp:DropDownList ID="ddl_Province" runat="server" DataSourceID="SqlDataSource1" DataTextField="cityName" DataValueField="id" AutoPostBack="True" OnTextChanged="ddl_Province_TextChanged"></asp:DropDownList>
+            <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:CityDBConnectionString %>" SelectCommand="SELECT * FROM [city] WHERE ([type] = @type)" OnSelecting="SqlDataSource1_Selecting">
+                <SelectParameters>
+                    <asp:Parameter DefaultValue="1" Name="type" Type="Int32" />
+                </SelectParameters>
+            </asp:SqlDataSource>
+            城市：<asp:DropDownList ID="ddl_City" runat="server" AutoPostBack="True" DataSourceID="SqlDataSource2" DataTextField="cityName" DataValueField="id" OnTextChanged="ddl_City_TextChanged"></asp:DropDownList>
+            <asp:SqlDataSource ID="SqlDataSource2" runat="server" ConnectionString="<%$ ConnectionStrings:CityDBConnectionString %>" SelectCommand="SELECT * FROM [city]"></asp:SqlDataSource>
+            区县：<asp:DropDownList ID="ddl_county" runat="server" DataSourceID="SqlDataSource3" DataTextField="cityName" DataValueField="id"></asp:DropDownList>
+            <asp:SqlDataSource ID="SqlDataSource3" runat="server" ConnectionString="<%$ ConnectionStrings:CityDBConnectionString %>" SelectCommand="SELECT * FROM [city]" OnSelecting="SqlDataSource3_Selecting"></asp:SqlDataSource>
+        </div>
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-- 
Gitee