Question

我的代码有问题，我需要制作一个显示图表的页面，以及一个用于更改图表类型的下拉列表

图表显示正确，但是下拉列表控件什么都不做，有人可以帮忙吗？我还想要选择在3种图表类型上使用3D

  <%@ Page Title="" Language="VB" MasterPageFile="~/Site.master" AutoEventWireup="false" CodeFile="test.aspx.vb" Inherits="admin_test" %>

<asp:Content ID="Content1" ContentPlaceHolderID="HeadContent" Runat="Server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" Runat="Server">

  <script type="text/javascript" language="javascript">
  function showContent(i) {
      if (document.getElementById('statContent' + i).style.display == 'none') {
          document.getElementById('statContent' + i).style.display = 'block';
      } else {
          document.getElementById('statContent' + i).style.display = 'none';
      }
  } 
</script> 
            choose chart display type: 
<asp:dropdownlist id="ChartTypeList" runat="server" AutoPostBack="True" 
CssClass="spaceright" Width="112px">
                    <asp:ListItem Value="Column" Selected="True">Column 2D</asp:ListItem>
                    <asp:ListItem Value="Column">Column 3D</asp:ListItem>
                    <asp:ListItem Value="Line">Line 2D</asp:ListItem>
                    <asp:ListItem Value="Line">Line 3D</asp:ListItem>
                    <asp:ListItem Value="Pie">Pie 2D</asp:ListItem>
                    <asp:ListItem Value="Pie">Pie 3D</asp:ListItem>
            </asp:dropdownlist><br />

 <asp:Chart ID="Chart1" runat="server" DataSourceID="SqlDataSource1" >
  <series>
    <asp:Series Name="Series1" ChartType="Pie" XValueMember="suburb" 
      YValueMembers="username">
    </asp:Series>
  </series>
  <chartareas>
    <asp:ChartArea Name="ChartArea1">
    </asp:ChartArea>
  </chartareas>
</asp:Chart>


    <asp:SqlDataSource ID="SqlDataSource1" runat="server" 
    ConnectionString="<%$ ConnectionStrings:ConnectionString %>" 
    SelectCommand="SELECT suburb, COUNT(username) AS username FROM member GROUP BY suburb">
        </asp:SqlDataSource>
</asp:Content>

Answer 1

我没有看到OnSelectedIndexChanged为您下拉列表列出的任何功能。你告诉它回发但不告诉它应该做什么。

你应该有类似的东西：

<asp:dropdownlist id="ChartTypeList" runat="server" AutoPostBack="True" 
CssClass="spaceright" Width="112px" onselectedindexchanged="ChartTypeList_SelectedIndexChanged">

和代码隐藏

protected void ChartTypeList_SelectedIndexChanged(object sender, EventArgs e)
{
//change the chart code
}

Answer 2

我自己解决了这个问题，只是想我会发布它以便任何人搜索这是正确的代码背后：

Protected Sub DropDownList_SelectedIndexChanged(sender As Object, e As System.EventArgs) Handles DropDownList.SelectedIndexChanged
    'keep charts hidden when not selected
    If (DropDownList.SelectedValue = "hide") Then
        Chart1.Visible = False
        'Columns
    ElseIf (DropDownList.SelectedValue = "Column 3D") Then
        Chart1.Series(0).ChartType = DataVisualization.Charting.SeriesChartType.Column
        Chart1.ChartAreas(0).Area3DStyle.Enable3D = True
        Chart1.Visible = True
    ElseIf (DropDownList.SelectedValue = "Column") Then
        Chart1.Series(0).ChartType = DataVisualization.Charting.SeriesChartType.Column
        Chart1.ChartAreas(0).Area3DStyle.Enable3D = False
        Chart1.Visible = True

        'Pies
    ElseIf (DropDownList.SelectedValue = "Pie 3D") Then
        Chart1.Series(0).ChartType = DataVisualization.Charting.SeriesChartType.Pie
        Chart1.ChartAreas(0).Area3DStyle.Enable3D = True
        Chart1.Visible = True
    ElseIf (DropDownList.SelectedValue = "Pie") Then
        Chart1.Series(0).ChartType = DataVisualization.Charting.SeriesChartType.Pie
        Chart1.ChartAreas(0).Area3DStyle.Enable3D = False
        Chart1.Visible = True

        'Lines
    ElseIf (DropDownList.SelectedValue = "Line 3D") Then
        Chart1.Series(0).ChartType = DataVisualization.Charting.SeriesChartType.Line
        Chart1.ChartAreas(0).Area3DStyle.Enable3D = True
        Chart1.Visible = True
    ElseIf (DropDownList.SelectedValue = "Line") Then
        Chart1.Series(0).ChartType = DataVisualization.Charting.SeriesChartType.Line
        Chart1.ChartAreas(0).Area3DStyle.Enable3D = False
        Chart1.Visible = True
    End If
End Sub

这是正确的代码：

 <asp:dropdownlist id="DropDownList" runat="server" AutoPostBack="True" 
                    OnSelectedIndexChanged="DropDownList_SelectedIndexChanged" >
                    <asp:ListItem value="hide" Selected="True">Select</asp:ListItem> 
                    <asp:ListItem Value="Pie">Pie Chart</asp:ListItem>
                    <asp:ListItem Value="Pie 3D">Pie Chart 3D</asp:ListItem>
                    <asp:ListItem Value="Column" >Column Chart</asp:ListItem>
                    <asp:ListItem Value="Column 3D">Column Chart 3D</asp:ListItem>
                    <asp:ListItem Value="Line">Line Chart</asp:ListItem>
                    <asp:ListItem Value="Line 3D">Line Chart 3D</asp:ListItem>
                    </asp:dropdownlist><br />

 <asp:Chart ID="Chart1" runat="server" Width="450px" Height="450px" DataSourceID="SqlDataSource1" Visible="false"  >
      <series>
         <asp:Series Name="Series1" XValueMember="suburb" YValueMembers="username">
         </asp:Series>
      </series>
        <chartareas>
            <asp:ChartArea Name="ChartArea1">
            </asp:ChartArea>
        </chartareas>
 </asp:Chart>

    <asp:SqlDataSource ID="SqlDataSource1" runat="server" 
    ConnectionString="<%$ ConnectionStrings:ConnectionString %>" 
    SelectCommand="SELECT suburb, COUNT(username) AS username FROM member GROUP BY suburb">
    </asp:SqlDataSource>

下拉列表不会更改图表类型

2 个答案: