vb.net 实现dropdownlist二级无刷新联动~！

说说vb.net ajaxpro 实现dropdownlist二级无刷新联动~！

Html写法：

< div class ="div_RSL" >
< asp:DropDownList ID ="DropDownList1" runat ="server" DataSourceID ="proID" DataTextField ="proName"AutoPostBack="false" DataValueField ="proID" >
</asp:DropDownList>
< asp:SqlDataSource ID ="proID" runat ="server" ConnectionString="<%$ ConnectionStrings:opperajaxConnectionString % >"SelectCommand="SELECT [proID], [proName] FROM [TB_province] ORDER BY [proID]"> </asp:SqlDataSource>
< asp:DropDownList ID ="DropDownList2" runat ="server" >
</asp:DropDownList>
</div>

这里dropdownlist1是服务器控件绑定，很方便~！

.写法：

function ShowCity(id)
{
     var res= Other_Register2.GetCity(id).value;
     var drop = document.getElementById( "<%=DropDownList2.UniqueID %>");
     drop.length=0;
     for( var i=0;i<res.Rows.length;i++)    
            {        
             drop.options.add( new Option(res.Rows[i].TB_cityName,res.Rows[i].TB_cityID));
            }    
}

alert(res)将返回一个[object object]类型

alert(res.rows)将返回一个object类型

alert(res.rows[0].value)将返回一个[object object]类型

如果返回null类型，接收不到datatable数据，则可能是你的ajaxpro.2.dll并不支持datatable输出，建议你下载文章末尾ajaxpro.2.dll附件~！

vb.net写法：

Sub Page_Load() Sub Page_Load( ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
     If Not Page.IsPostBack Then
        DropDownList1.Attributes( "onchange") = "ShowCity(this.options[selectedIndex].value)"
     End If        

AjaxPro.Utility.RegisterTypeForAjax(GetType(Other_Register2))
End Sub

Function GetCity() Function GetCity( ByVal sproid) As DataTable
Dim sqlconnection As New SqlConnection(ShareFunction.GetDBConnectionString())
sqlconnection.Open()
Dim sql As String = "select TB_cityID,TB_cityName from TB_city where proID=" & ShareFunction.SafeRequest(sproid, 1) & ""
Dim dataada As New SqlDataAdapter(sql, sqlconnection)
Dim dt As New DataTable
dataada.Fill(dt)
Return dt
End Function

这里使用dataadapter对象将查询数据存入datatable中~！