谷歌饼图未显示在浏览器中

本文关键字：浏览器 显示 谷歌 | 更新日期: 2023-09-27 18:29:58

我正试图从List对象填充一个数据表，然后将结果显示在饼图中。由于某种原因，我无法识别饼图没有显示在浏览器中（空白页）。下面是我的代码。有人能试着运行这个代码并识别是错误吗！。。。因为我不能确定我错了。

Default.aspx

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <script type="text/javascript" src="https://www.google.com/jsapi"></script>
    <script type="text/javascript">
        google.load("visualization", "1", { packages: ["corechart"] });
        google.setOnLoadCallback(drawChart);
        function drawChart(dataValues) {
            var data = new google.visualization.DataTable();
            data.AddColumn('string', 'Locality');
            data.AddColumn('number', 'Frequency');
            for (var i = 0; i < dataValues.length; i++) {
                data.AddRow(dataValues[i].aString, dataValues[i].anInt);
            }
            var options = { 'title': 'Pie Chart Test',
                'width': 900,
                'height': 500
            };
               var chart =  new google.visualization.PieChart(document.getElementById('piechart'));
               chart.draw(data, options);
        }
    </script>
  </head>
  <body>
    <div id="piechart" style="width: 900px; height: 500px;"></div>
  </body>
</html>

背后的代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.Script.Serialization;
public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            List<Items> dataList = new List<Items>();
            dataList.Add(new Items("A", 10));
            dataList.Add(new Items("B", 20));
            dataList.Add(new Items("C", 30));
            JavaScriptSerializer jss = new JavaScriptSerializer();
            ClientScript.RegisterStartupScript(this.GetType(), "Test", string.Format("<script type='"text/javascript'">drawVisualization({0});</script>", jss.Serialize(dataList)));
        }
    }
    public class Items
    {
        public string aString = "";
        public int anInt = 0;
        public Items(string _aString, int _anInt)
        {
        aString = _aString;
        anInt = _anInt;
        }
    }
}

谢谢

谷歌饼图未显示在浏览器中

JavaScript区分大小写。方法名称为.addColumn()和.addRow()，但您使用的是.AddColumn()和.AddRow()。检查您的JavaScript控制台是否存在错误。你应该找到一条类似undefined is not a function的消息。

.addRow()方法将一个数组作为其参数，但您要传入两个标量值。用方括号括起来：data.addRow([dataValues[i].aString, dataValues[i].anInt])。

您也可能在使用RegisterStartupScript()时遇到问题。您的启动脚本可能会在可视化包加载完成之前运行。相反，我会将值嵌入页面上的一个隐藏字段中，并从脚本中读取该值。

<asp:HiddenField runat="server" ID="ChartData" />

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        List<Items> dataList = new List<Items>();
        dataList.Add(new Items("A", 10));
        dataList.Add(new Items("B", 20));
        dataList.Add(new Items("C", 30));
        JavaScriptSerializer jss = new JavaScriptSerializer();
        this.ChartData.Value = jss.Serialize(dataList);
    }
}

function drawChart() {
    var dataValues = JSON.parse(document.getElementById("<%= ChartData.ClientID %>").value);
    // The rest of the function as written
}

应用了所有更改的代码段：

google.load("visualization", "1", { packages: ["corechart"] });
google.setOnLoadCallback(drawChart);
function drawChart() {
    var dataValues = JSON.parse(document.getElementById("ChartData").value);
    var data = new google.visualization.DataTable();
    data.addColumn('string', 'Locality');
    data.addColumn('number', 'Frequency');
    for (var i = 0; i < dataValues.length; i++) {
        data.addRow([dataValues[i].aString, dataValues[i].anInt]);
    }
    var options = { 'title': 'Pie Chart Test',
        'width': 900,
        'height': 500
    };
    var chart =  new google.visualization.PieChart(document.getElementById('piechart'));
    chart.draw(data, options);
}
<script type="text/javascript" src="https://www.google.com/jsapi"></script>
<input type="hidden" id="ChartData" value="[{&quot;aString&quot;:&quot;A&quot;,&quot;anInt&quot;:10},{&quot;aString&quot;:&quot;B&quot;,&quot;anInt&quot;:20},{&quot;aString&quot;:&quot;C&quot;,&quot;anInt&quot;:30}]" />
<div id="piechart" style="width: 900px; height: 500px;"></div>

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