/// <summary>
/// 拼接两个 Expression 。
/// </summary>
/// <typeparam name="T">表达式中的元素类型</typeparam>
/// <param name="left">左边的 Expression</param>
/// <param name="right">右边的 Expression</param>
/// <param name="func">表达式拼接的具体逻辑</param>
/// <returns>拼接完成的 Expression</returns>
public static Expression <Func <T, bool> > MakeBinary <T>(this Expression <Func <T, bool> > left,
Expression <Func <T, bool> > right, Func <Expression, Expression, Expression> func)
{
var data = Combinate(right.Parameters, left.Parameters).ToArray();
if (left.Parameters.Count != right.Parameters.Count || !data.All(p => p.Key.Type == p.Value.Type))
{
throw new InvalidOperationException("Parameter error.");
}
right = ParameterReplace.Replace(right, data) as Expression <Func <T, bool> >;
return(Expression.Lambda <Func <T, bool> >(func(left.Body, right.Body), left.Parameters));
}
/// <summary>
/// Replaces the specified e.
/// </summary>
/// <param name="e">The e.</param>
/// <param name="paramList">The param list.</param>
/// <returns></returns>
public static Expression Replace(Expression e, IEnumerable <KeyValuePair <ParameterExpression, ParameterExpression> > paramList)
{
var item = new ParameterReplace(paramList);
return(item.Visit(e));
}
