/// <summary>
/// 生成验证复杂字段是否重复的Lambda
/// </summary>
/// <param name="Entity">源数据</param>
/// <param name="para">源数据类型</param>
/// <returns>Where语句</returns>
public override Expression GetExpression(T Entity, ParameterExpression para)
{
ParameterExpression midPara = Expression.Parameter(typeof(V), "tm2");
//获取中间表的List
var list = _middleExp.Compile().Invoke(Entity);
if (list == null)
{
return(null);
}
List <Expression> allExp = new List <Expression>();
Expression rv = null;
//循环中间表数据
foreach (var li in list)
{
List <Expression> innerExp = new List <Expression>();
bool needBreak = false;
//循环中间表要检查重复的字段
foreach (var SubFieldExp in _subFieldExps)
{
//拼接字段表达式，使left等于类似 x.field 的形式
Expression left = Expression.Property(midPara, SubFieldExp.GetPropertyName());
//如果字段是nullable类型的，则拼接value，形成类似 x.field.Value的形式
if (left.Type.IsGeneric(typeof(Nullable <>)) == true)
{
left = Expression.Property(left, "Value");
}
//如果字段是string类型，则拼接trim，形成类似 x.field.Trim()的形式
if (left.Type == typeof(string))
{
left = Expression.Call(left, typeof(String).GetMethod("Trim", Type.EmptyTypes));
}
//使用当前循环的中间表的数据获取字段的值
object vv = SubFieldExp.Compile().Invoke(li);
//如果值为空则跳过
if (vv == null)
{
needBreak = true;
continue;
}
//如果值为空字符串且没要求必填，则跳过
if (vv is string && vv.ToString() == "")
{
var requiredAttrs = li.GetType().GetSingleProperty(SubFieldExp.GetPropertyName()).GetCustomAttributes(typeof(RequiredAttribute), false).ToList();
if (requiredAttrs == null || requiredAttrs.Count == 0)
{
needBreak = true;
continue;
}
else
{
var requiredAtt = requiredAttrs[0] as RequiredAttribute;
if (requiredAtt.AllowEmptyStrings == true)
{
needBreak = true;
continue;
}
}
}
//如果值为字符串，调用trim函数
if (vv is string)
{
vv = vv.ToString().Trim();
}
//拼接形成 x.field == value的形式
ConstantExpression right = Expression.Constant(vv);
BinaryExpression equal = Expression.Equal(left, right);
innerExp.Add(equal);
}
if (needBreak)
{
continue;
}
//拼接多个 x.field==value，形成 x.field==value && x.field1==value1 .....的形式
Expression exp = null;
if (innerExp.Count == 1)
{
exp = innerExp[0];
}
if (innerExp.Count > 1)
{
exp = Expression.And(innerExp[0], innerExp[1]);
for (int i = 2; i < innerExp.Count; i++)
{
exp = Expression.And(exp, innerExp[i]);
}
}
//调用any函数，形成 .Any(x=> x.field==value && x.field1==value1....)的形式
if (exp != null)
{
var any = Expression.Call(
typeof(Enumerable),
"Any",
new Type[] { typeof(V) },
Expression.Property(para, _middleExp.GetPropertyName()),
Expression.Lambda <Func <V, bool> >(exp, new ParameterExpression[] { midPara }));
allExp.Add(any);
}
}
//拼接多个any函数形成 .Any(x=> x.field==value && x.field1==value1....) || .Any(x=> x.field==value && x.field1==value1....)的形式并返回
if (allExp.Count == 1)
{
rv = allExp[0];
}
if (allExp.Count > 1)
{
rv = Expression.OrElse(allExp[0], allExp[1]);
for (int i = 2; i < allExp.Count; i++)
{
rv = Expression.OrElse(rv, allExp[i]);
}
}
return(rv);
}
public Expression GetExpression(T Entity, ParameterExpression para)
{
ParameterExpression midPara = Expression.Parameter(typeof(V), "tm2");
var list = MiddleExp.Compile().Invoke(Entity);
List <Expression> allExp = new List <Expression>();
Expression rv = null;
foreach (var li in list)
{
List <Expression> innerExp = new List <Expression>();
bool needBreak = false;
foreach (var SubFieldExp in SubFieldExps)
{
Expression left = Expression.Property(midPara, UtilsTool.GetPropertyName(SubFieldExp));
if (left.Type.IsGenericType && left.Type.GetGenericTypeDefinition() == typeof(Nullable <>))
{
left = Expression.Property(left, "Value");
}
if (left.Type == typeof(string))
{
left = Expression.Call(left, typeof(String).GetMethod("Trim", Type.EmptyTypes));
}
object vv = SubFieldExp.Compile().Invoke(li);
if (vv == null)
{
needBreak = true;
continue;
}
if (vv is string && vv.ToString() == "")
{
var requiredAttrs = li.GetType().GetProperty(UtilsTool.GetPropertyName(SubFieldExp)).GetCustomAttributes(typeof(RequiredAttribute), false);
if (requiredAttrs == null || requiredAttrs.Length == 0)
{
needBreak = true;
continue;
}
else
{
var requiredAtt = requiredAttrs[0] as RequiredAttribute;
if (requiredAtt.AllowEmptyStrings == true)
{
needBreak = true;
continue;
}
}
}
if (vv is string)
{
vv = vv.ToString().Trim();
}
ConstantExpression right = Expression.Constant(vv);
BinaryExpression equal = Expression.Equal(left, right);
innerExp.Add(equal);
}
if (needBreak)
{
continue;
}
Expression exp = null;
if (innerExp.Count == 1)
{
exp = innerExp[0];
}
if (innerExp.Count > 1)
{
exp = Expression.And(innerExp[0], innerExp[1]);
for (int i = 2; i < innerExp.Count; i++)
{
exp = Expression.And(exp, innerExp[i]);
}
}
if (exp != null)
{
var any = Expression.Call(
typeof(Enumerable),
"Any",
new Type[] { typeof(V) },
Expression.Property(para, UtilsTool.GetPropertyName(MiddleExp)),
Expression.Lambda <Func <V, bool> >(exp, new ParameterExpression[] { midPara }));
allExp.Add(any);
}
}
if (allExp.Count == 1)
{
rv = allExp[0];
}
if (allExp.Count > 1)
{
rv = Expression.Or(allExp[0], allExp[1]);
for (int i = 2; i < allExp.Count; i++)
{
rv = Expression.Or(rv, allExp[i]);
}
}
return(rv);
}
