public class Compare<T, C> : IEqualityComparer<T>
{
private Func<T, C> _getField;
public Compare(Func<T, C> getfield)
{
this._getField = getfield;
}
public bool Equals(T x, T y)
{
return EqualityComparer<C>.Default.Equals(_getField(x), _getField(y));
}
public int GetHashCode(T obj)
{
return EqualityComparer<C>.Default.GetHashCode(this._getField(obj));
}
}
Compare
public static class CommonHelper
{
/// <summary>
/// 自定义Distinct扩展方法
/// </summary>
/// <typeparam name="T">要去重的对象类</typeparam>
/// <typeparam name="C">自定义去重的字段类型</typeparam>
/// <param name="source">要去重的对象</param>
/// <param name="getfield">获取自定义去重字段的委托</param>
/// <returns></returns>
public static IEnumerable<T> MyDistinct<T, C>(this IEnumerable<T> source, Func<T, C> getfield)
{
return source.Distinct(new Compare<T, C>(getfield));
}
}
//定义一个类继承IEqualityComparer接口
public class ModelComparer : IEqualityComparer<Model>
{
public bool Equals(Model x, Model y)
{
return x.Title.ToUpper() == y.Title.ToUpper();
}
public int GetHashCode(Model obj)
{
return obj.Title.ToUpper().GetHashCode();
}
}
modelList = modelList.Distinct(new ModelComparer()).ToList();
var title = modelList.GroupBy(m => m.Title.ToLower().Trim()).Select(m => new { ID = m.FirstOrDefault().ID });
modelList = modelList.Where(m => title.Select(mo => mo.ID).Contains(m.ID)).ToList();
foreach (var item in modelList)
{
Console.WriteLine(item.ID + " " + item.Title);
}