protected override Expression VisitBinary(BinaryExpression node)
{
string left, right, op, condition;
Match match;
Visit(node.Left);
bool singleBool = false;
if (node.Left.NodeType == ExpressionType.MemberAccess)
{
var leftExp = node.Left as MemberExpression;
if (ExpressionReflector.GetNullableOrSelfType(leftExp.Type).FullName == "System.Boolean" && leftExp.Type.Assembly.GlobalAssemblyCache)
{
//x.IsEnabled这种情况
if (node.Right.NodeType == ExpressionType.Constant)
{
//x.IsEnabled=true
}
else if (_conditionStack.Count > 0)
{
//x.IsEnabled && ......
_list.Add(_conditionStack.Peek(), true);//.Push("[" + leftExp.Member.Name + "]");
singleBool = true;
}
}
}
if (node.Left.NodeType == ExpressionType.Not)
{
var unaryExp = node.Left as UnaryExpression;
if (unaryExp.Operand.NodeType == ExpressionType.MemberAccess)
{
var leftExp = unaryExp.Operand as MemberExpression;
if (leftExp.Type.FullName == "System.Boolean" && leftExp.Type.Assembly.GlobalAssemblyCache)
{
//x.IsEnabled这种情况
if (node.Right.NodeType == ExpressionType.Constant)
{
//x.IsEnabled=true
}
else if (_conditionStack.Count > 0)
{
//x.IsEnabled && ......
_list.Add(_conditionStack.Peek(), false);//.Push("[" + leftExp.Member.Name + "]");
singleBool = true;
}
else
{
bool value = (bool)_constStack.Pop();
if (value)
{
_conditionStack.Push("1=1");
}
else
{
_conditionStack.Push("1=2");
}
}
}
}
}
//此时已获取到了值，一般情况下访问右支就是为了找值，所以直接组合
if (singleBool)
{
right = _conditionStack.Pop();
left = _conditionStack.Pop();
op = "=";
condition = string.Format("({0} {1} {2})", left, op, right);
_conditionStack.Push(condition);
}
if (node.NodeType == ExpressionType.ArrayIndex)
{
//处理数组访问，此时right存的是index，所以跳过Right访问
var constExp = node.Right as ConstantExpression;
var index = Convert.ToInt32(constExp.Value);
var arrayObject = _constStack.Pop() as Array;
object arrayValue = arrayObject.GetValue(index);
while (_memberStack.Count > 0)
{
var member = _memberStack.Pop();
if (member.MemberType == MemberTypes.Field)
{
arrayValue = ((FieldInfo)member).GetValue(arrayValue);
}
else if (member.MemberType == MemberTypes.Property)
{
arrayValue = ((PropertyInfo)member).GetValue(arrayValue, null);
}
else
{
throw new NotSupportedException("未知的成员类型：" + member.MemberType);
}
}
_list.Add(_conditionStack.Peek(), arrayValue);
return(node);
}
else
{
if (node.Right is ConstantExpression)
{
var constExp = node.Right as ConstantExpression;
_list.Add(_conditionStack.Peek(), constExp.Value);
}
else
{
Visit(node.Right);
}
}
if (_constStack.Count > 0)
{
//常量计算
object c1 = _constStack.Pop();
object c2 = _constStack.Pop();
bool c3 = false;
switch (node.NodeType)
{
case ExpressionType.Equal:
c3 = c1 == c2;
break;
case ExpressionType.GreaterThan:
if (c1 == null && c2 == null)
{
c3 = true;
}
else
{
c3 = false;
}
break;
}
if (c3)
{
_conditionStack.Push("1=1");
}
else
{
_conditionStack.Push("1=2");
}
}
else
{
right = _conditionStack.Pop();
left = _conditionStack.Pop();
op = string.Empty;
switch (node.NodeType)
{
case ExpressionType.AndAlso:
op = "and";
break;
case ExpressionType.OrElse:
op = "or";
break;
case ExpressionType.Equal:
op = "=";
break;
case ExpressionType.GreaterThanOrEqual:
op = ">=";
break;
case ExpressionType.GreaterThan:
op = ">";
break;
case ExpressionType.LessThan:
op = "<";
break;
case ExpressionType.LessThanOrEqual:
op = "<=";
break;
case ExpressionType.ArrayIndex:
op = "=";
break;
default:
throw new NotImplementedException("未实现逻辑关系:" + node.NodeType);
}
var lastParameter = _list.LastOrDefault();
if (lastParameter.Value == null)
{
right = "null";
_list.Remove(lastParameter.Key);
}
condition = string.Format("({0} {1} {2})", left, op, right);
match = Regex.Match(condition, @"(.*)? = null");
if (match.Success || (match = Regex.Match(condition, "null = (.*)")).Success)
{
_conditionStack.Push(match.Groups[1].Value + " is null)");
}
else
{
_conditionStack.Push(condition);
}
}
return(node);
}
