Document 文件类的常用方法

版权声明： https://blog.csdn.net/weixin_41722928/article/details/86367747

BsonElement

（Bson元素）
  
  

Bson元素是一个name/value的键值对。
  
  

  
  
document.Add( new BsonElement( "age", 21)); // OK, but next line is shorter
document.Add( "age", 21); // creates BsonElement automatically
  
  

BsonDocument

BsonDocument是name/value键值对的集合。
  
  

BsonDocument构造函数
  
  

• BsonDocument()
• BsonDocument(string name, BsonValue value)

上面是用的比较多

• BsonDocument(BsonElement element)
• BsonDocument(Dictionary<string, object> dictionary)
• BsonDocument(Dictionary<string, object> dictionary, IEnumerable<string> keys)
• BsonDocument(IDictionary dictionary)
• BsonDocument(IDictionary dictionary, IEnumerable<string> keys)
• BsonDocument(IDictionary<string, object> dictionary)
• BsonDocument(IDictionary<string, object> dictionary, IEnumerable<string> keys)
• BsonDocument(IEnumerabe<BsonElement> elements)
• BsonDocument(params BsonElement[] elements)
• BsonDocument(bool allowDuplicateNames)

创建一个新的document并且调用Add和Set函数

  
  
BsonDocument book = new BsonDocument();
book.Add( "author", "Ernest Hemingway");
book.Add( "title", "For Whom the Bell Tolls");
  
  

另外一种方式
  
  

  
  
BsonDocument book = new BsonDocument()
.Add( "author", "Ernest Hemingway")
.Add( "title", "For Whom the Bell Tolls");
  
  

使用c#的collection初始化语法（推荐）
  
  

  
  
BsonDocument book = new BsonDocument {
{ "author", "Ernest Hemingway" },
{ "title", "For Whom the Bell Tolls" }
};
编译器会将它翻译成调用Add函数的方式
  
  

  
  
BsonDocument book = new BsonDocument();
book.Add( "author", "Ernest Hemingway");
book.Add( "title", "For Whom the Bell Tolls");
不要缺少里面的大括号，不然就会像下面一样
  
  

  
  
BsonDocument bad = new BsonDocument {
"author", "Ernest Hemingway"
};
编译成：
  
  

  
  
BsonDocument bad = new BsonDocument();
bad.Add( "author");
bad.Add( "Ernest Hemingway");
  
  

创建嵌套的BSON documents
  
  

  
  
BsonDocument nested = new BsonDocument {
{ "name", "John Doe" },
{ "address", new BsonDocument {
{ "street", "123 Main St." },
{ "city", "Centerville" },
{ "state", "PA" },
{ "zip", 12345}
}}
};
”address”是一个嵌套的document
  
  

ADD函数

• Add(BsonElement element)
• Add(Dictionary<string, object> dictionary)
• Add(Dictionary<string, object> dictionary, IEnumerable<string> keys)
• Add(IDictionary dictionary)
• Add(IDictionary dictionary, IEnumerable<string> keys)
• Add(IDictionary<string, object> dictionary)
• Add(IDictionary<string, object> dictionary, IEnumerable<string> keys)
• Add(IEnumerable<BsonElement> elements)
• Add(string name, BsonValue value)
• Add(string name, BsonValue value, bool condition)

如果里面的属性值是null的话，add函数将不把数据加入到document中

  
  
BsonDocument document = new BsonDocument {
{ "name", name },
{ "city", city }, // not added if city is null
{ "dob", dob, dobAvailable } // not added if dobAvailable is false
};
可以翻译成如下：
  
  

  
  
BsonDocument document = new BsonDocument();
document.Add( "name", name);
if (city != null) {
document.Add( "city", city);
}
if (dobAvailable) {
document.Add( "dob", dob);
}
如果想 add一个BsonNull值，可以使用C #中的null联合
  
  

  
  
BsonDocument = new BsonDocument {
{ "city", city ?? BsonConstants.Null }
};
  
  

获取BsonDocument的元素elements
  
  

• BsonValue this[int index]
• BsonValue this[string name]
• BsonValue this[string name, BsonValue defaultValue]

返回的是BsonValue值，例子如下

  
  
BsonDocument book;
string author = book[ "author"].AsString;
DateTime publicationDate = book[ "publicationDate"].AsDateTime;
int pages = book[ "pages", -1].AsInt32; // default value is -1
  
  

BsonArray

这个类是用来表示BSON 数组。

构造函数

• BsonArray()
• BsonArray(IEnumerable<bool> values)
• BsonArray(IEnumerable<BsonValue> values)
• BsonArray(IEnumerable<DateTime> values)
• BsonArray(IEnumerable<double> values)
• BsonArray(IEnumerable<int> values)
• BsonArray(IEnumerable<long> values)
• BsonArray(IEnumerable<ObjectId> values)
• BsonArray(IEnumerable<string> values)
• BsonArray(IEnumerable values)

Add 和 AddRange 函数

• BsonArray Add(BsonValue value)
• BsonArray AddRange(IEnumerable<bool> values)
• BsonArray AddRange(IEnumerable<BsonValue> values)
• BsonArray AddRange(IEnumerable<DateTime> values)
• BsonArray AddRange(IEnumerable<double> values)
• BsonArray AddRange(IEnumerable<int> values)
• BsonArray AddRange(IEnumerable<long> values)
• BsonArray AddRange(IEnumerable<ObjectId> values)
• BsonArray AddRange(IEnumerable<string> values)
• BsonArray AddRange(IEnumerable values)

  
  
// traditional approach
BsonArray a1 = new BsonArray();
a1.Add( 1);
a2.Add( 2);

// fluent interface
BsonArray a2 = new BsonArray().Add( 1).Add( 2);

// values argument
int[] values = new int[] { 1, 2 };
BsonArray a3 = new BsonArray(values);

// collection initializer syntax
BsonArray a4 = new BsonArray { 1, 2 };
  
  

 

访问

  
  
BsonArray array = new BsonArray { "Tom", 39 };
string name = array[ 0].AsString;
int age = array[ 1].AsInt32;