从 TableAttribute Dapper.Contrib 获取表名

Question

我正在使用 Dapper 和 Dapper.Contrib 来映射数据库中的对象。

我有一个类名，我为这个类定义了表名，因为它与实际的类名不同。

类：

[Table("tblUser")]
public class User
{
    public int Id { get; set; }
    public string Title { get; set; }
}

如何获取表名设置的表数据注解属性？

编辑：

我已经使用了以下功能来使其正常工作

var tAttribute =
    (TableAttribute)typeof(T).GetCustomAttributes(typeof(TableAttribute), true)[0];

tableName = tAttribute.Name;

Answer 1

protected string TableName<T>()
{
    // Check if we've already set our custom table mapper to TableNameMapper.
    if (SqlMapperExtensions.TableNameMapper != null)
        return SqlMapperExtensions.TableNameMapper(typeof(T));

    // If not, we can use Dapper default method "SqlMapperExtensions.GetTableName(Type type)" which is unfortunately private, that's why we have to call it via reflection.
    string getTableName = "GetTableName";
    MethodInfo getTableNameMethod = typeof(SqlMapperExtensions).GetMethod(getTableName, BindingFlags.NonPublic | BindingFlags.Static);

    if (getTableNameMethod == null)
        throw new ArgumentOutOfRangeException($"Method '{getTableName}' is not found in '{nameof(SqlMapperExtensions)}' class.");

    return getTableNameMethod.Invoke(null, new object[] { typeof(T) }) as string;
}

用法：

string postTableName = TableName<Post>();

或者你可以打开原来的SqlMapperExtensions.GetTableName(Type type)方法并复制它的代码。

Answer 2

我在控制台应用程序 .NET Framework 4.6.2 中对此进行了测试。如果您想了解有关该扩展程序的更多信息，请参阅SqlMappperExtensions。

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            SqlMapperExtensions.TableNameMapper = TableNameMapper;
            var name = TableNameMapper(typeof(User));
        }

        private static string TableNameMapper(Type type)
        {
            dynamic tableattr = type.GetCustomAttributes(false).SingleOrDefault(attr => attr.GetType().Name == "TableAttribute");
            var name = string.Empty;

            if (tableattr != null)
            {
                name = tableattr.Name;
            }

            return name;
        }
    }

    [Table("tblUser")]
    public class User
    {
        public int Id { get; set; }
        public string Title { get; set; }
    }
}