protected override Expression VisitMethodCall(MethodCallExpression m)
{
if (m.Method.DeclaringType == typeof(String) && m.Method.Name == "StartsWith")
{
if (ExpressionTreeHelpers.IsSpecificMemberExpression(m.Object, typeof(Place), "Name") ||
ExpressionTreeHelpers.IsSpecificMemberExpression(m.Object, typeof(Place), "State"))
{
locations.Add(ExpressionTreeHelpers.GetValueFromExpression(m.Arguments[0]));
return(m);
}
}
else if (m.Method.Name == "Contains")
{
Expression valuesExpression = null;
if (m.Method.DeclaringType == typeof(Enumerable))
{
if (ExpressionTreeHelpers.IsSpecificMemberExpression(m.Arguments[1], typeof(Place), "Name") ||
ExpressionTreeHelpers.IsSpecificMemberExpression(m.Arguments[1], typeof(Place), "State"))
{
valuesExpression = m.Arguments[0];
}
}
else if (m.Method.DeclaringType == typeof(List <string>))
{
if (ExpressionTreeHelpers.IsSpecificMemberExpression(m.Arguments[0], typeof(Place), "Name") ||
ExpressionTreeHelpers.IsSpecificMemberExpression(m.Arguments[0], typeof(Place), "State"))
{
valuesExpression = m.Object;
}
}
if (valuesExpression == null || valuesExpression.NodeType != ExpressionType.Constant)
{
throw new Exception("Could not find the location values.");
}
ConstantExpression ce = (ConstantExpression)valuesExpression;
IEnumerable <string> placeStrings = (IEnumerable <string>)ce.Value;
// Add each string in the collection to the list of locations to obtain data about.
foreach (string place in placeStrings)
{
locations.Add(place);
}
return(m);
}
return(base.VisitMethodCall(m));
}
internal static bool IsMemberEqualsValueExpression(Expression exp, Type declaringType, string memberName)
{
if (exp.NodeType != ExpressionType.Equal)
{
return(false);
}
BinaryExpression be = (BinaryExpression)exp;
// Assert.
if (ExpressionTreeHelpers.IsSpecificMemberExpression(be.Left, declaringType, memberName) &&
ExpressionTreeHelpers.IsSpecificMemberExpression(be.Right, declaringType, memberName))
{
throw new Exception("Cannot have 'member' == 'member' in an expression!");
}
return(ExpressionTreeHelpers.IsSpecificMemberExpression(be.Left, declaringType, memberName) ||
ExpressionTreeHelpers.IsSpecificMemberExpression(be.Right, declaringType, memberName));
}
protected override Expression VisitBinary(BinaryExpression be)
{
if (be.NodeType == ExpressionType.Equal)
{
if (ExpressionTreeHelpers.IsMemberEqualsValueExpression(be, typeof(Place), "Name"))
{
locations.Add(ExpressionTreeHelpers.GetValueFromEqualsExpression(be, typeof(Place), "Name"));
return(be);
}
else if (ExpressionTreeHelpers.IsMemberEqualsValueExpression(be, typeof(Place), "State"))
{
locations.Add(ExpressionTreeHelpers.GetValueFromEqualsExpression(be, typeof(Place), "State"));
return(be);
}
else
{
return(base.VisitBinary(be));
}
}
else
{
return(base.VisitBinary(be));
}
}
