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怎样使当DropDownList1改变时也改变相应的DropDownList2的值？
实现二级联动。如省市联动啊。 以下有代码。 将DropDownList1的AutoPostBack属性设为true 导入命名空间 Imports System.Data Imports System.Data.SqlClient Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load '在此处放置初始化页的用户代码 'Dim mydb As DB If Not IsPostBack Then '绑定省 'Dim connstr As String = "server=.;database=mag_Web;User ID=sa;password=;" 'Dim myconn As SqlConnection 'myconn = New SqlConnection(connstr) 'myconn = mydb.GetSqlconn() Dim myconn As SqlConnection = myconnection.GetSqlconn myconn.Open() Dim mycommand As New SqlCommand("select * from province", myconn) Dim myreader As SqlDataReader myreader = mycommand.ExecuteReader() DropDownList1.DataSource = myreader DropDownList1.DataTextField = "proName" DropDownList1.DataValueField = "proID" DropDownList1.DataBind() myreader.Close() '绑定市 Dim mycity As New SqlCommand("select * from city where proID=" + DropDownList1.SelectedValue, myconn) Dim myreader1 As SqlDataReader myreader1 = mycity.ExecuteReader() DropDownList2.DataSource = myreader1 DropDownList2.DataTextField = "cityName" DropDownList2.DataValueField = "cityID" DropDownList2.DataBind() myreader1.Close() myconn.Close() End If 'Dim myconn As SqlConnection End Sub Private Sub btnReset_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnReset.Click txtUserName.Text = "" txtPassword1.Text = "" txtPassword2.Text = "" RequiredFieldValidator1.Visible = False And RequiredFieldValidator2.Visible = False 'CompareValidator1.Visible = False End Sub Private Sub btnSumbit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSumbit.Click 'Dim connstr As String = "server=.;database=mag_Web;User ID=sa;password=;" Dim myconn As SqlConnection = myconnection.GetSqlconn 'myconn = New SqlConnection(connstr) myconn.Open() Dim mycommand As New SqlCommand("insert into mag_Users(UserName,UserPassword,UserProvince,UserCity) values('" + txtUserName.Text + "','" + txtPassword1.Text + "','" + DropDownList1.SelectedItem.Text + "','" + DropDownList2.SelectedItem.Text + "')") mycommand.Connection = myconn mycommand.ExecuteNonQuery() myconn.Close() Response.Redirect("Login2.aspx") End Sub Private Sub DropDownList1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles DropDownList1.SelectedIndexChanged Dim proID As String proID = DropDownList1.SelectedValue 'Dim connstr As String = "server=.;database=mag_Web;User ID=sa;password=;" Dim myconn As SqlConnection = myconnection.GetSqlconn 'myconn = New SqlConnection(connstr) 'myconn = mydb.GetSqlconn() myconn.Open() Dim mycommand As New SqlCommand("select * from city where proID=" + proID, myconn) Dim myreader As SqlDataReader myreader = mycommand.ExecuteReader() DropDownList2.DataSource = myreader DropDownList2.DataTextField = "cityName" DropDownList2.DataValueField = "cityID" DropDownList2.DataBind() myreader.Close() myconn.Close() End Sub其他回答
将DropDownList1的AutoPostBack属性设为true 在DropDownList1_SelectedIndexChanged 中 将DropDownList1.SelectedValue 赋给DropDownList2版权声明：本文内容由互联网用户自发贡献，该文观点仅代表作者本人。本站仅提供信息存储空间服务，不拥有所有权，不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容， 请联系我们举报，一经查实，本站将立刻删除。发布者：全栈程序员-站长，转载请注明出处：https://javaforall.net/161259.html原文链接：https://javaforall.net
