/// <summary>
/// 翻译Update部分的Lambda表达式。得到要更新的属性或字段。
/// </summary>
/// <typeparam name="T">使用条件的类型参数。</typeparam>
/// <param name="update">Update表达式。</param>
/// <returns>翻译结果。</returns>
private static BsonDocument TranslateUpdate <T>(Expression <Func <T> > update) where T : new()
{
if (update.NodeType != ExpressionType.Lambda)
{
throw new Exception("参数Update不是正确的Lambda表达式");
}
var updatebody = update.Body as MemberInitExpression;
var analysiser = new InitExpresPropAnalysiser();
var updatedPropList = analysiser.Analysiser(updatebody);
var mongoUpdate = new MongoDB.Driver.Builders.UpdateBuilder();
foreach (var membVal in updatedPropList)
{
mongoUpdate.SetWrapped(membVal.MemberRoute, membVal.Value);
}
return(mongoUpdate.ToBsonDocument());
}
/// <summary>
/// Returns an update builder used in the mongodb's update procedure;
/// prepares a builder that sets some properties on insert and increases some other properties on update
/// </summary>
/// <returns></returns>
public IMongoUpdate GetUpdateBuilder()
{
MongoDB.Driver.Builders.UpdateBuilder SetOnInsertBuilder = new MongoDB.Driver.Builders.UpdateBuilder();
MongoDB.Driver.Builders.UpdateBuilder IncBuilder = new MongoDB.Driver.Builders.UpdateBuilder();
//object's own props
var props = this.GetType().GetProperties();
//build updates
foreach (var p in props)
{
if (!PropsIncreasedOnUpdate.Contains(p.Name))
{
//use dynamic here so it can be then converted to BsonValue by the mongodb driver
dynamic pValue = p.GetValue(this);
if (pValue == null)
{
SetOnInsertBuilder.SetOnInsert(p.Name, BsonNull.Value);
}
else
{
if (p.Name != "_id") //do not set id on insert, let db generate it!
{
SetOnInsertBuilder.SetOnInsert(p.Name, pValue);
}
}
}
else
{
IncBuilder.Inc(p.Name, p.GetValue(this) as dynamic);
}
}
//output combined update builders
return(MongoDB.Driver.Builders.Update.Combine(SetOnInsertBuilder, IncBuilder));
}
public static bool Update(string dbName, string collectionName, MongoDB.Driver.IMongoQuery query, MongoDB.Driver.Builders.UpdateBuilder update)
{
MongoCollection collection = GetCollection(dbName, collectionName);
WriteConcernResult result = collection.Update(query, update);
return(result.UpdatedExisting);
}
