/// <summary>
/// 将尺码横排显示
/// </summary>
/// <param name="products">原数据集</param>
/// <param name="propertyNameForSize">转换到尺码列下的属性</param>
/// <param name="propertyNamesForAggregation">转换完毕后需要汇总的属性集合</param>
public DataTable TransferSizeToHorizontal <T>(IEnumerable <T> products, string propertyNameForSize = "Quantity", IEnumerable <string> propertyNamesForSum = null) where T : ProductShow
{
if (propertyNamesForSum == null)
{
propertyNamesForSum = new string[] { propertyNameForSize }
}
;
var props = typeof(T).GetProperties();
var dt = new DataTable();
IEnumerable <string> sizeNames = products.Select(p => p.SizeName).Distinct();
foreach (var prop in props)
{
if (prop.Name == "SizeName")
{
//dt.Columns.AddRange(VMGlobal.Sizes.Select(s => new DataColumn(s.Name, typeof(int))).ToArray());
dt.Columns.AddRange(sizeNames.Select(s => new DataColumn(s, typeof(int))).ToArray());
}
else
{
dt.Columns.Add(new DataColumn(prop.Name, prop.PropertyType));
}
}
var func = GetGetDelegate <T>(dt.Columns, propertyNamesForSum, sizeNames);
var scs = products.Select(o => o.StyleCode + o.ColorCode).Distinct().ToArray();
foreach (string sc in scs)
{
var ps = products.Where(o => (o.StyleCode + o.ColorCode) == sc);
var row = dt.Rows.Add(func(ps.ElementAt(0)));
foreach (var p in ps)
{
row[p.SizeName] = GetGetDelegate <T>(propertyNameForSize)(p);
foreach (var psum in propertyNamesForSum)
{
switch (dt.Columns[psum].DataType.Name.ToLower())
{
case "int32":
row[psum] = (int)row[psum] + (int)GetGetDelegate <T>(psum)(p);
break;
case "decimal":
row[psum] = (decimal)row[psum] + (decimal)GetGetDelegate <T>(psum)(p);
break;
case "float":
row[psum] = (float)row[psum] + (float)GetGetDelegate <T>(psum)(p);
break;
}
}
}
}
return(dt);
}
Func <T, object[]> GetGetDelegate <T>(DataColumnCollection props, IEnumerable <string> propertyNamesForSum, IEnumerable <string> sizeNames)
{
var param_obj = Expression.Parameter(typeof(T), "obj");
List <Expression> memberExps = new List <Expression>();
foreach (DataColumn prop in props)
{
if (sizeNames.Contains(prop.ColumnName) || propertyNamesForSum.Contains(prop.ColumnName))
{
memberExps.Add(Expression.Convert(Expression.Constant(0), typeof(object)));
}
else
{
memberExps.Add(Expression.Convert(Expression.Property(param_obj, prop.ColumnName), typeof(object)));
}
}
Expression newArrayExpression = Expression.NewArrayInit(typeof(object), memberExps);
return(Expression.Lambda <Func <T, object[]> >(newArrayExpression, param_obj).Compile());
}
Func <T, object> GetGetDelegate <T>(string propertyName)
{
if (_dicFunc == null)
{
_dicFunc = new Dictionary <string, Delegate>();
}
if (!_dicFunc.ContainsKey(propertyName))
{
var param_obj = Expression.Parameter(typeof(T), "obj");
//lambda的方法体 u.Age
var pGetter = Expression.Convert(Expression.Property(param_obj, propertyName), typeof(object));
//编译lambda
_dicFunc.Add(propertyName, Expression.Lambda <Func <T, object> >(pGetter, param_obj).Compile());
}
return((Func <T, object>)_dicFunc[propertyName]);
}
}
public static object FastGetValue <T>(this PropertyInfo property, T t)
{
return(GetGetDelegate <T>(property)(t));
}
