How to delay loading a property with linq to sql external mapping?

问题

I have a table that contains some blob fields that I don't want to load by default.

In a dbml file it is possible to set the delay loaded property for such fields.

Is there a similar option for external mapping files?

回答1:

I'm not familiar with "external mapping files", but this is basically how you do lazy loading with LINQ-to-SQL:

    private System.Data.Linq.Link<String> _content;
    [Column(Name = "content", DbType = "NVarChar(MAX) NOT NULL", Storage = "_content")]
    public String Content
    {
        get { return this._content.Value; }
        set { this._content.Value = value; }
    }

Using System.Data.Linq.Link<String> as the private variable causes that property to be delay loaded, unless delay loading is disabled on the DataContext.

回答2:

I believe you would have to do something like what Daniel Schaffer said in code, but without the [Column] attribute, since you would define the mapping in the XML file.

来源：https://stackoverflow.com/questions/499183/how-to-delay-loading-a-property-with-linq-to-sql-external-mapping