private static Expression <Func <T, bool> > CombineLambdas <T>(this Expression <Func <T, bool> > left,
Expression <Func <T, bool> > right, ExpressionType expressionType)
{
//Remove expressions created with Begin<T>()
if (IsExpressionBodyConstant(left))
{
return(right);
}
ParameterExpression p = left.Parameters[0];
SubstituteParameterVisitor visitor = new SubstituteParameterVisitor();
visitor.Sub[right.Parameters[0]] = p;
Expression body = Expression.MakeBinary(expressionType, left.Body, visitor.Visit(right.Body));
return(Expression.Lambda <Func <T, bool> >(body, p));
}
private static Expression <Func <T, bool> > CombineLambdas <T>(this Expression <Func <T, bool> > left, Expression <Func <T, bool> > right, ExpressionType expressionType)
{
var visitor = new SubstituteParameterVisitor
{
Sub =
{
[right.Parameters[0]] = left.Parameters[0]
}
};
Expression body = Expression.MakeBinary(expressionType, left.Body, visitor.Visit(right.Body));
return(Expression.Lambda <Func <T, bool> >(body, left.Parameters[0]));
}
private static Expression <Func <T, bool> > CombineLambdas <T>(this Expression <Func <T, bool> > left,
Expression <Func <T, bool> > right, ExpressionType expressionType)
{
// If the existing expression is a constant, it was created with Begin<T>() and it should be removed.
if (IsExpressionBodyConstant(left))
{
return(right);
}
var p = left.Parameters[0];
var visitor = new SubstituteParameterVisitor();
visitor.SubstitutionMap[right.Parameters[0]] = p;
var body = Expression.MakeBinary(expressionType, left.Body, visitor.Visit(right.Body));
return(Expression.Lambda <Func <T, bool> >(body, p));
}
private static Expression <Func <T, bool> > CombineLambdas <T>(this Expression <Func <T, bool> > left,
Expression <Func <T, bool> > right, ExpressionType expressionType)
{
if (left == null || IsExpressionBodyConstant(left))
{
return(right);
}
if (right == null)
{
return(left);
}
var p = left.Parameters[0];
var visitor = new SubstituteParameterVisitor();
visitor.Sub[right.Parameters[0]] = p;
Expression body = Expression.MakeBinary(expressionType, left.Body, visitor.Visit(right.Body));
return(Expression.Lambda <Func <T, bool> >(body, p));
}