如何动态地将XElements添加到XML文件?
好的,所以我的程序将在运行时保存用户从NumericUpDown控件给出的任何数量的XElements。我的XmlTextWriter写这个的方法如下:如何动态地将XElements添加到XML文件?
public void XMLWriteNewL4Module()
{
int i;
String workingDir = Directory.GetCurrentDirectory();
//create a new file in the working directory
XmlTextWriter textWriter = new XmlTextWriter("Level4Modules.xml", null);
//opens the document
textWriter.WriteStartDocument(); //Document Start
//first student
textWriter.WriteStartElement("Module"); //Module start
//Module title element
textWriter.WriteStartElement("Title", ""); //Title start
textWriter.WriteString(this.textBoxModuleTitle.Text);
textWriter.WriteEndElement(); //Title end
//Module code element
textWriter.WriteStartElement("Code", ""); //Code start
textWriter.WriteString(this.textBoxModuleCode.Text);
textWriter.WriteEndElement(); //Code end
//Credit value element
textWriter.WriteStartElement("Credit Value", ""); //Credit value start
textWriter.WriteString(this.textBoxModuleCreditValue.Text);
textWriter.WriteEndElement(); //Credit value end
//Assessments element
textWriter.WriteStartElement("Assessments", ""); //Assessments start
for (i = 0; i < numericUpDownNoOfAssessments.Value; i++)
{
textWriter.WriteStartElement("Assessment", ""); //Assessment start
textWriter.WriteStartElement("Assessment Type", ""); //Assessment type start
textWriter.WriteString((comboBoxAssessments[i] as ComboBox).Text);
textWriter.WriteEndElement(); //Assessment type end
textWriter.WriteStartElement("Assessment Grade", ""); //Assessment grade start
textWriter.WriteString((textBoxAssessments[i] as TextBox).Text);
textWriter.WriteEndElement(); //Assessment grade end
textWriter.WriteStartElement("Assessment Weighting", ""); //Assessment weighting start
textWriter.WriteString((assessmentWeightingTextBox[i] as TextBox).Text);
textWriter.WriteEndElement(); //Assessment weighting end
textWriter.WriteEndElement(); //Assessment end
}
textWriter.WriteEndElement(); //Assessments end
textWriter.WriteEndElement(); //Module end
//end the document
textWriter.WriteEndDocument(); //Document end
//close the writer
textWriter.Close();
Console.ReadLine();
}
,但这种方式并不让我追加的XML文件,所以我想是这样写的:
public void XMLWriteNewL4Module()
{
String workingDir = Directory.GetCurrentDirectory();
int i;
if (File.Exists(workingDir + @"Level4Modules.xml") == false)
{
//create a new file in the working directory
XmlTextWriter textWriter = new XmlTextWriter("Level4Modules.xml", null);
textWriter.WriteStartElement("Modules");
textWriter.WriteEndElement();
textWriter.Close();
}
XElement xDoc = XElement.Load(workingDir + @"Level4Modules.xml");
xDoc.Add(
new XElement("Module",
new XElement("Title", this.textBoxStudentFirstName.Text),
new XElement("Code", this.textBoxStudentSurname.Text),
new XElement("Credit Value", this.textBoxStudentIDNewUser.Text),
new XElement("Assessments",
for (i = 0; i < numericUpDownNoOfAssessments.Value; i++)
{
new XElement("Assessment Type", (comboBoxAssessments[i] as ComboBox).Text),
new XElement("Assessment Grade",),
new XElement("Assessment Weighting",))
}
));
xDoc.Save(workingDir + @"\Students.xml");
}
和这并未”让我在新的XElement声明中使用for循环(这是可以理解的),所以我需要一种解决方法,因为我绝对难住。它显示的错误消息是“无效的表达式”,因为显然c#不喜欢你在XElement中启动for循环。 任何想法如何解决这个问题?
您可以将for循环放入一个新方法,该方法返回XElement [],并调用需要子项的方法。 事情是这样的:
C#
new XElement("Module",
new XElement("Title", this.textBoxStudentFirstName.Text),
new XElement("Code", this.textBoxStudentSurname.Text),
new XElement("Credit Value", this.textBoxStudentIDNewUser.Text),
new XElement("Assessments", GetAssessments())); //the returned items will be added as child items to the "Assessments" node
C#
XElement[] GetAssessments()
{
var result = new List<XElement>();
for (int i = 0; i < numericUpDownNoOfAssessments.Value; i++)
{
result.Add(new XElement("Assessment Type", (comboBoxAssessments[i] as ComboBox).Text));
result.Add(new XElement("Assessment Grade", ""));
result.Add(new XElement("Assessment Weighting", ""));
}
return result.ToArray();
}
如果有一些相关的背景信息,您可以通过它进入新的方法作为参数。 我希望我能帮上忙。
非常感谢。我试过这个,意识到我错误地命名了一些东西,但设法让它起作用。非常感谢 –
你可以使用Enumerable.Range
扩展名,它应该允许你在XElement
里构造嵌套元素。
public void XMLWriteNewL4Module()
{
String workingDir = Directory.GetCurrentDirectory();
int i;
if (File.Exists(workingDir + @"Level4Modules.xml") == false)
{
//create a new file in the working directory
XmlTextWriter textWriter = new XmlTextWriter("Level4Modules.xml", null);
textWriter.WriteStartElement("Modules");
textWriter.WriteEndElement();
textWriter.Close();
}
XElement xDoc = XElement.Load(workingDir + @"Level4Modules.xml");
xDoc.Add(
new XElement("Module",
new XElement("Title", this.textBoxStudentFirstName.Text),
new XElement("Code", this.textBoxStudentSurname.Text),
new XElement("Credit Value", this.textBoxStudentIDNewUser.Text),
new XElement("Assessments", Enumerable.Range(0,numericUpDownNoOfAssessments.Value)
.Select(i=>
{
return new XElement[] {
new XElement("Assessment Type", (comboBoxAssessments[i] as ComboBox).Text),
new XElement("Assessment Grade"),
new XElement("Assessment Weighting")
};
}))));
xDoc.Save(workingDir + @"\Students.xml");
}
嗨,试图用这个想法和C#不喜欢: 新的XElement(“评估”,Enumerable.Range(0,numericUpDownNoOfAssessments.Value) 。选择(i => 部分。错误消息读取: 最好的重载方法匹配有一些无效参数。 –
你能告诉我们什么是'Xml'结构看起来像什么?也是一个预期的Xml? –