在 C# 控制台应用程序中，如何生成 Google Charts API 请求并将结果保存为图像？

Question

是否可以在控制台应用程序中调用 Google Charts API 并将结果保存为 JPEG 或 PNG 文件？我可以在网络应用程序中轻松完成此操作，只是不太确定如何在 C# 中完成此操作。

非常感谢

- https://chart.googleapis.com/chart

Answer 1

您可以使用 Charts API 的 googlechartsharp 包装器获取一个网址，您可以通过该网址查看图表。

使用 HttpWebRequest 和 HttpWebResponse 类（或根据 Joey 的回答使用 WebClient 类），您可以将响应流捕获为字节数组（ image）并将其写入具有正确扩展名的文件（*.png 文件）。像这样的东西：

string chartUrl = chart.GetUrl();
byte[] chartBytes = null;
WebClient client = new WebClient();
chartBytes = client.DownloadData(chartUrl);

using (var memStream = new MemoryStream())
{
    memStream.Write(chartBytes, 0, chartBytes.Length);
}

File.WriteAllBytes("C:\temp\myChart.png", chartBytes);

Answer 2

使用 WebClient 类及其 下载数据 或 DownloadFile 方法。构建要检索的 URL 由您决定。

Answer 3

我添加了我的图表生成器类（工作完美）。只需调用它（如下所示）添加您自己的事件方法即可在生成图表后捕获图表并将其保存到 HDD。

调用类并生成图表：

   ChartGenerator charBartGen = new ChartGenerator();
            charBartGen.ChartCreated += new ChartCreatedEventHandler(charBartGen_ChartCreated);
            charBartGen.CreateBarChart(pictureBox2.Height, pictureBox2.Width,
                stats.MaxChecks,
                "Past 7 days",
                stats.Last7DayChecks1, stats.Last7DayChecks2);

实际类：

   public class ChartGenerator
{
    public event ChartCreatedEventHandler ChartCreated;

    public string CreatePieChartUrl(int pHeight, int pWidth,
        string[] pSeries, string pTitle, int[] pData)
    {

        string st = String.Format(Misc.EnUk,
        @"http://chart.apis.google.com/chart?chs={0}x{1}&cht=p3&chd=t:", pWidth, pHeight);
        for (int i = 0; i < pData.Length; i++)
        {
            st += pData[i].ToString(Misc.EnUk) + ",";
        }

        st = st.TrimEnd(',');

        st += "&chdl=";
        for (int i = 0; i < pData.Length; i++)
        {
            st += pSeries[i].Replace(" ", "+") + "|";
        }
        st = st.TrimEnd('|');

        st += "&chtt=";
        st += pTitle.Replace(" ", "+") + "|";

        return st;
    }

    public void CreatePieChart(int pHeight, int pWidth,
        string[] pSeries, string pTitle, int[] pData)
    {
        string url = CreatePieChartUrl(pHeight, pWidth,
         pSeries, pTitle, pData);
        Thread th = new Thread(new ParameterizedThreadStart(CreateChartAsync));
        th.Start(url);
    }

    public string CreateBarChartUrl(int pHeight, int pWidth, int pMax,
        string pTitle, int[] pData1, int[] pData2)
    {
      string st = String.Format(Misc.EnUk,
        @"http://chart.apis.google.com/chart?chxr=0,0,{0}&chxt=y&chbh=a&chs={1}x{2}&cht=bvs&chco=4D89F9,C6D9FD&chds=0,{0},0,{0}&chd=t:", 
            pMax, pWidth, pHeight);

        for (int i = 0; i < pData1.Length; i++)
        {
            st += pData1[i].ToString(Misc.EnUk) + ",";
        }
        st = st.TrimEnd(',');
        st += "|";

        for (int i = 0; i < pData2.Length; i++)
        {
            st += pData2[i].ToString(Misc.EnUk) + ",";
        }
        st = st.TrimEnd(',');

        st += "&chtt=";
        st += pTitle.Replace(" ", "+");

        return st;
    }

    public void CreateBarChart(int pHeight, int pWidth,int pMax,
      string pTitle, int[] pData1,int[] pData2)
    {
        string url = CreateBarChartUrl(pHeight, pWidth, pMax,
        pTitle, pData1, pData2);
        Thread th = new Thread(new ParameterizedThreadStart(CreateChartAsync));
        th.Start(url);
    }

    private void CreateChartAsync(object pUrl)
    {
        string url = pUrl as string;

        try
        {
            if (url != null)
            {
                using (Stream stream = GetPageContentStream(url, false))
                {
                    Image img = Image.FromStream(stream);

                    if (img != null)
                    {
                        if (ChartCreated != null)
                        {
                            ChartCreated(this, new ChartCreatedEventArgs(img));
                        }
                    }
                }
            }
        }
        catch (Exception err)
        {
            Debug.Fail(err.Message);
        }
    }

    /// <summary>
    /// Gets the stream of the given url
    /// </summary>
    /// <param name="url">The url</param>
    /// <param name="file">Whether this is a web file stream or a HttpWebRequest</param>
    /// <returns></returns>
    public static Stream GetPageContentStream(string url, bool file)
    {
        try
        {
            WebRequest wreq;
            WebResponse wres;

            if (file)
            {
                wreq = System.Net.FileWebRequest.Create(url);
            }
            else
            {
                wreq = HttpWebRequest.Create(url);
                HttpWebRequest httpwrqst = wreq as HttpWebRequest;

                if (httpwrqst != null)
                {
                    httpwrqst.AllowAutoRedirect = false;
                    httpwrqst.Timeout = 10000;
                }
            }

            wres = wreq.GetResponse();
            return wres.GetResponseStream();
        }
        catch(Exception err)
        {
            Debug.Fail(err.Message);
            Logger.AppLogger.Instance.LogError("GetPageContentStream", err);
            return null;
        }
    }

}

public delegate void ChartCreatedEventHandler(object sender,ChartCreatedEventArgs e);

[Serializable]
public class ChartCreatedEventArgs : EventArgs
{
    private readonly Image mImage;

    public ChartCreatedEventArgs()
    {
    }

    public ChartCreatedEventArgs(Image pImage)
    {
        mImage = pImage;
    }

    public Image Image
    {
        get
        {
            return mImage;
        }
    }

}