XmlReader.MoveToFirstAttribute XmlReader.MoveToFirstAttribute XmlReader.MoveToFirstAttribute XmlReader.MoveToFirstAttribute Method

定义

当在派生类中被重写时,移动到第一个属性。When overridden in a derived class, moves to the first attribute.

public:
 abstract bool MoveToFirstAttribute();
public abstract bool MoveToFirstAttribute ();
abstract member MoveToFirstAttribute : unit -> bool
Public MustOverride Function MoveToFirstAttribute () As Boolean

返回

如果属性存在(读取器移动到第一个属性),则为 true;否则为 false(读取器的位置不更改)。true if an attribute exists (the reader moves to the first attribute); otherwise, false (the position of the reader does not change).

异常

在上一次异步操作完成之前调用了 XmlReader 方法。An XmlReader method was called before a previous asynchronous operation finished. 在此情况下,会引发 InvalidOperationException 并显示消息“异步操作已在进行中。”In this case, InvalidOperationException is thrown with the message "An asynchronous operation is already in progress."

示例

下面的示例获取第一个属性的值。The following example gets the value of the first attribute.

reader.ReadToFollowing("book");
reader.MoveToFirstAttribute();
string genre = reader.Value;
Console.WriteLine("The genre value: " + genre);
reader.ReadToFollowing("book")
reader.MoveToFirstAttribute()
Dim genre As String = reader.Value
Console.WriteLine("The genre value: " + genre)

适用于