public static string AsPath(this LambdaExpression expression)
{
if (expression == null)
{
return((string)null);
}
string path;
ExpressionExtensions.TryParsePath(expression.Body, out path);
return(path);
}
private static bool TryParsePath(Expression expression, out string path)
{
path = (string)null;
Expression expression1 = ExpressionExtensions.RemoveConvert(expression);
MemberExpression memberExpression = expression1 as MemberExpression;
MethodCallExpression methodCallExpression = expression1 as MethodCallExpression;
if (memberExpression != null)
{
string name = memberExpression.Member.Name;
string path1;
if (!ExpressionExtensions.TryParsePath(memberExpression.Expression, out path1))
{
return(false);
}
path = path1 == null ? name : path1 + "." + name;
}
else if (methodCallExpression != null)
{
if (methodCallExpression.Method.Name == "Select" && methodCallExpression.Arguments.Count == 2)
{
string path1;
string path2;
if (!ExpressionExtensions.TryParsePath(methodCallExpression.Arguments[0], out path1) ||
(path1 == null || !(methodCallExpression.Arguments[1] is LambdaExpression lambdaExpression)) ||
(!ExpressionExtensions.TryParsePath(lambdaExpression.Body, out path2) || path2 == null))
{
return(false);
}
path = path1 + "." + path2;
return(true);
}
if (methodCallExpression.Method.Name == "Where")
{
throw new NotSupportedException("Filtering an Include expression is not supported");
}
if (methodCallExpression.Method.Name == "OrderBy" ||
methodCallExpression.Method.Name == "OrderByDescending")
{
throw new NotSupportedException("Ordering an Include expression is not supported");
}
return(false);
}
return(true);
}