我知道这是一个老问题,但在我的最后一个项目中遇到了同样的问题,所以我创建了一个使用属性的自己的映射器。
我定义了一个名为ColumnNameAttribute.cs的属性类。
using System;
namespace DapperHelper.Attributes
{
[System.AttributeUsage(AttributeTargets.All, Inherited = true, AllowMultiple = true)]
sealed class ColumNameAttribute : Attribute
{
private string _columName;
public string ColumnName
{
get { return _columName; }
set { _columName = value; }
}
public ColumNameAttribute(string columnName)
{
_columName = columnName;
}
}
}
定义属性后,我实现了一个动态映射器,它使用Dapper的Query
方法,但作为Query<T>
工作:
using Dapper;
using DapperHelper.Attributes;
using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Reflection;
using System.Web.Routing;
namespace DapperHelper.Tools
{
public class DynamicMapper<T> :IDisposable where T : class, new()
{
private readonly Dictionary<string, PropertyInfo> _propertiesMap;
public DynamicMapper()
{
_propertiesMap = new Dictionary<string, PropertyInfo>();
PropertyInfo[] propertyInfos = typeof(T).GetProperties(BindingFlags.Public | BindingFlags.Instance);
foreach (PropertyInfo propertyInfo in propertyInfos)
{
if (propertyInfo.GetCustomAttribute(typeof(ColumNameAttribute)) is ColumNameAttribute columNameAttribute)
{
_propertiesMap.Add(columNameAttribute.ColumnName, propertyInfo);
}
else
{
_propertiesMap.Add(propertyInfo.Name, propertyInfo);
}
}
}
public List<T> QueryDynamic(IDbConnection dbConnection, string sqlQuery)
{
List<dynamic> results = dbConnection.Query(sqlQuery).ToList();
List<T> output = new List<T>();
foreach (dynamic dynObj in results)
{
output.Add(AssignPropertyValues(dynObj));
}
return output;
}
private T AssignPropertyValues(dynamic dynamicObject)
{
T output = new T();
RouteValueDictionary dynamicObjProps = new RouteValueDictionary(dynamicObject);
foreach (var propName in dynamicObjProps.Keys)
{
if (_propertiesMap.TryGetValue(propName, out PropertyInfo propertyMapped)
&& dynamicObjProps.TryGetValue(propName, out object value))
{
propertyMapped.SetValue(output, value);
}
}
return output;
}
public void Dispose()
{
_propertiesMap.Clear();
}
}
}
要使用它,您需要引用您的模型类并定义属性:
using DapperHelper.Attributes;
namespace Testing
{
public class Sample
{
public int SomeColumnData { get; set; }
[ColumnName("Your Column Name")]
public string SpecialColumn{ get; set; }
}
}
然后你可以实现像这样的东西:
DynamicMapper<Sample> mapper = new DynamicMapper<Sample>()
List<Sample> samples = mapper.QueryDynamic(connection, "SELECT * FROM Samples")
我希望这能帮助到寻找替代方案的人。