Mapping a URI to String-field in LINQ-to-SQL

问题

I'm trying to store a URI as a string in a database, using LINQ.

[Column(Name = "Url", DbType = "nvarchar(255)")]
public Uri Url
{
    get
    {
        return new Uri(_url);
    }
    set
    {
        _url = value.AbsoluteUri;
    }
}

private string _url;

This maps nicely to my database design, however, when trying to fetch data using this code:

int id = 3;
_serie = new DataContext(connString).GetTable<Serie>();
var serie = _serie.FirstOrDefault(s => s.Id == id);

At the last line, I get an exception

System.InvalidCastException: Invalid cast from System.String to System.Uri etc

What do I need to do get correctly handle a URI in my code, but store it is a nvarchar(255) in my database? It seems simple, but I can't figure out where I'm doing it wrong.

回答1:

As always, writing down the question helped me realize the problem. The following code fixed my problem:

public Uri Url
{
    get
    {
        return new Uri(_url);
    }
    set
    {
        _url = value.AbsoluteUri;
    }
}

[Column(Name = "Url", DbType = "nvarchar(255)")]
private string _url;

来源：https://stackoverflow.com/questions/1612010/mapping-a-uri-to-string-field-in-linq-to-sql