每次单击鼠标时将数据添加到 xml 文件

Question

每次鼠标事件发生时，我都必须将数据添加到 xml 文件！这是我的代码，您看一下后我会更好地向您解释。

 private void pictureBox1_MouseClick(object sender, MouseEventArgs e)
    {


            if (radioButton1.Checked==true)
            {
                if (a > 3 && a < 11)
                {

                    rect.Width = 0;
                    rect.Height = 0;
                    pictureBox1.Invalidate();


                 raghu =   img.imageToByteArray(pictureBox1.Image);


                    int radius = 10; //Set the number of pixel you want to use here
                    //Calculate the numbers based on radius
                    int x0 = Math.Max(e.X - (radius / 2), 0),
                        y0 = Math.Max(e.Y - (radius / 2), 0),
                        x1 = Math.Min(e.X + (radius / 2), pictureBox1.Width),
                        y1 = Math.Min(e.Y + (radius / 2), pictureBox1.Height);
                    Bitmap bm = pictureBox1.Image as Bitmap; //Get the bitmap (assuming it is stored that way)
                    for (int ix = x0; ix < x1; ix++)
                    {
                        for (int iy = y0; iy < y1; iy++)
                        {
                            bm.SetPixel(ix, iy, Color.Black); //Change the pixel color, maybe should be relative to bitmap
                        }
                    }
                    pictureBox1.Refresh(); //Force refresh

                    //calculation part.
                    float u = l[p + 1] - l[p];
                    float v = m[p + 1] - m[p];
                    float w = (e.Y - m[p]) / v;//subtract from latitude
                    float z = (e.X - l[p]) / u;//add to longitude.
                    float latmin = h[p] - w;
                    float longmin = j[p] + z;

                    A1 = e.X - c[p];
                    A2 = e.Y - d[p];
                    B1 = c[p + 1] - c[p];
                    B2 = d[p + 1] - d[p];
                    A = Math.Sqrt(Math.Pow(A1, 2) + Math.Pow(A2, 2));
                    B = Math.Sqrt(Math.Pow(B1, 2) + Math.Pow(B2, 2));
                    dotproduct = A1 * B1 + A2 * B2;
                    theta = (180 / Math.PI) * Math.Acos(dotproduct / (A * B));
                    if (e.X < c[p])
                    {
                        theta1 = 360 - theta;
                    }
                    else
                    {
                        theta1 = theta;
                    }
                    textBox2.Text = string.Format("Latitude:{0}°{1}'{2}''\n Longitude:{3}°{4}'{5}'' \n ICAO LOC: {6} {7} \n Distance: {8:0.0} Nm", g[p] + (int)latmin / 60, (int)latmin % 60,(int) (((h[p]-w) % 60 - (int)(latmin % 60)) * 60), i[p] + (int)longmin / 60, (int)longmin % 60, (int)((longmin % 60 - (int)(longmin % 60)) * 60), textBox1.Text, Math.Abs((int)theta1), Math.Sqrt(Math.Pow((A1/u)* 60, 2) + Math.Pow((A2/v) * 60, 2))); 

现在有很多计算部分是不必要的。但是我要在 textBox2 中打印的数据（最后一行代码）很重要。每次我打印的所有数据都应该添加到 Xml 文件中单击图片框上的鼠标...

所以我尝试通过添加这种方式使用 xdocument 来实现..

             XDocument xdoc = XDocument.Load(string.Format("{0}.xml", textBox3.Text));
                    XElement ParentNode= xdoc.Root.Element(string.Format("{0}",radioButton1.Text));
                    XElement node= new XElement("WayPoints",new XElement("LatitudeDegrees",g[p] + (int)latmin / 60 ,
                                     new XAttribute("Minutes",(int)latmin % 60),
                                         new XAttribute("Seconds",(int)(((h[p] - w) % 60 - (int)(latmin % 60)) * 60)),
                                            new XElement("LongitudeDegrees",i[p] + (int)longmin / 60,
                                                new XAttribute("Minutes",(int)longmin % 60),
                                                  new XAttribute("seconds",(int)((longmin % 60 - (int)(longmin % 60)) * 60)),
                                                     new XElement ("IcaoLocator",textBox1.Text,
                                                         new XAttribute("angle",Math.Abs((int)theta1)),
                                                         new XElement("DistanceInNauticalMiles",Math.Sqrt(Math.Pow((A1 / u) * 60, 2) + Math.Pow((A2 / v) * 60, 2))

                )))));
                    ParentNode.Add(node);
                    xdoc.Save(string.Format("{0}.xml", textBox3.Text));

但问题是它说根元素丢失。

实际上我在 Xdocument 中加载的文件是，我

  using (XmlWriter writer = XmlWriter.Create(string.Format("{0}.xml", textBox3.Text)))
            { 
            }

之前已经在这里创建了它，如下所示（因为我担心如果在 Picturebox_Mouseclick 中创建它，它会被覆盖）

 private void pictureBox1_MouseDoubleClick(object sender, MouseEventArgs e)
    {

            if (a > 1 && a <= 3)
            {
                c[f] = e.X;
                d[f] = e.Y;
                a++;
                f++;
            }
          using (XmlWriter writer = XmlWriter.Create(string.Format("{0}.xml", textBox3.Text)))
            { 
            }
    }        

如果您不理解计算，请不要打扰，它特定于我的需求我只需要将数据打印到 xml 文件..请任何人帮助我..

这里有一个航点示例，

<?xml version="1.0" encoding="UTF-8"?>
<WayPoints>
  <Latitude>
    <Degrees>48</Degrees>
    <Minutes>31.7363644</Minutes>
  </Latitude>
  <Longitude>
    <Degrees>11</Degrees>
    <Minutes>57.53425</Minutes>
  </Longitude>
  <IcaoLocator>
    <Type>EDML</Type>
    <Angle>288</Angle>
    <DistanceInPixels>346</DistanceInPixels>
  </IcaoLocator>
</WayPoints>

但它只包含一个航点..我需要向这个 XML 文件添加很多航点。

Answer 1

这里的问题似乎是事实上（正如例外情况）xml 没有根元素。通过将 xml 的布局更改为如下所示，可以相当简单地解决此问题：

<?xml version="1.0" encoding="UTF-8"?>
<WayPoints>
   <WayPoint>
      <Latitude>
        <Degrees>48</Degrees>
        <Minutes>31.7363644</Minutes>
      </Latitude>
      <Longitude>
        <Degrees>11</Degrees>
        <Minutes>57.53425</Minutes>
      </Longitude>
      <IcaoLocator>
        <Type>EDML</Type>
        <Angle>288</Angle>
        <DistanceInPixels>346</DistanceInPixels>
      </IcaoLocator>
   </WayPoint>
   <WayPoint> <!-- New waypoint here, not at the root -->
      <Latitude>
        <Degrees>48</Degrees>
        <Minutes>31.7363644</Minutes>
      </Latitude>
      <Longitude>
        <Degrees>11</Degrees>
        <Minutes>57.53425</Minutes>
      </Longitude>
      <IcaoLocator>
        <Type>EDML</Type>
        <Angle>288</Angle>
        <DistanceInPixels>346</DistanceInPixels>
      </IcaoLocator>
   </WayPoint>
</WayPoints>

然后您应该能够执行以下操作：

var doc = XDocument.Load("PATH_TO_FILE.xml");
doc.Element("WayPoints").Add(new XElement("WayPoint", 
    new XElement("Latitude",
        new XElement("Degrees", 48),
        new XElement("Minutes", 31.7363644),
    ),
    new XElement("Longitude",
        new XElement("Degrees", 48),
        new XElement("Minutes", 31.7363644),
    ),
    new XElement("IcaoLocator",
        new XElement("Type", "EDML"),
        new XElement("Angle", 288),
        new XElement("DistanceInPixels", 346)
    )
);
doc.Save("PATH_TO_FILE.xml");

未测试（此计算机上没有 Visual Studio）。

Answer 2

当您使用 xml 编写器创建 xml 文件时，您不会在其中放入任何元素，因此当 XDocument 加载它时，它找不到根元素并抛出您收到的异常。

如果文件不存在，我建议跳过 xmlwriter 并将 XDocument 初始化为新的 XDocument：

XDocument xdoc;
if( File.Exist( string.Format("{0}.xml", textBox3.Text ) ) )
  xdoc = XDocument.Load( string.Format( "{0}.xml", textBox3.Text ) );
else
  xdoc = new XDocument(...);