Another reason I don't like LINQ
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Here's my error
System.ArgumentNullException: 'Value cannot be null.
Parameter name: values'... for this mess:
Columns.AddRange(obj.GetType().GetGenericArguments().FirstOrDefault()?.GetProperties().Where(p =>
{
return p.GetCustomAttributes(true).OfType().FirstOrDefault()?.Browsable ?? DefaultBrowsableState;
}).Select(p =>
{
return new ColumnHeader()
{
Name = p.Name,
Text = p.GetCustomAttributes(true).OfType().FirstOrDefault()?.DisplayName ?? p.Name
};
}).ToArray());The thing is, I know what it's trying to do, and the code makes sense to me even though I didn't write it. The LINQ isn't really that bad here. But the error message is just awful. I don't even know where to begin. Time to hand roll the same statement LINQless so I can debug it. So consider this my part 2 in why LINQ is for the birds.
Real programmers use butterflies
My crystal ball says your object's type doesn't contain any generic arguments, so you're passing
nulltoAddRange.var genericArguments = obj.GetType().GetGenericArguments();
if (genericArguments.Length != 0)
{
Columns.AddRange(genericArguments[0].GetProperties()
.Where(p => p.GetCustomAttributes(true).OfType<BrowsableAttribute>().FirstOrDefault()?.Browsable ?? DefaultBrowsableState)
.Select(p => new ColumnHeader
{
Name = p.Name,
Text = p.GetCustomAttributes(true).OfType<DisplayNameAttribute>().FirstOrDefault()?.DisplayName ?? p.Name,
});
}Throw in a custom extension method to simplify it slightly:
public static class AttributeExtensions
{
public static TAttribute GetCustomAttribute<TAttribute>(this ICustomAttributeProvider value, bool inherit = true)
where TAttribute : Attribute
{
if (value is null) throw new ArgumentNullException(nameof(value));object\[\] attributes = value.GetCustomAttributes(typeof(TAttribute), inherit); return attributes.Length == 0 ? null : (TAttribute)attributes\[0\]; }}
var genericArguments = obj.GetType().GetGenericArguments();
if (genericArguments.Length != 0)
{
Columns.AddRange(genericArguments[0].GetProperties()
.Where(p => p.GetCustomAttribute<BrowsableAttribute>()?.Browsable ?? DefaultBrowsableState)
.Select(p => new ColumnHeader
{
Name = p.Name,
Text = p.GetCustomAttribute<DisplayNameAttribute>()?.DisplayName ?? p.Name,
});
}
"These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer
-
Here's my error
System.ArgumentNullException: 'Value cannot be null.
Parameter name: values'... for this mess:
Columns.AddRange(obj.GetType().GetGenericArguments().FirstOrDefault()?.GetProperties().Where(p =>
{
return p.GetCustomAttributes(true).OfType().FirstOrDefault()?.Browsable ?? DefaultBrowsableState;
}).Select(p =>
{
return new ColumnHeader()
{
Name = p.Name,
Text = p.GetCustomAttributes(true).OfType().FirstOrDefault()?.DisplayName ?? p.Name
};
}).ToArray());The thing is, I know what it's trying to do, and the code makes sense to me even though I didn't write it. The LINQ isn't really that bad here. But the error message is just awful. I don't even know where to begin. Time to hand roll the same statement LINQless so I can debug it. So consider this my part 2 in why LINQ is for the birds.
Real programmers use butterflies
Which functions takes a "values" parameter? I would guess it's `Columns.AddRange()`? If so, then my first guess would be that the problem is with `obj.GetType().GetGenericArguments()` not having any items (length == 0). I guess this is one of the reasons we try to write readable code... so we also get more specific error messages. This one-liner nonsense is bad for everyone.
-
Here's my error
System.ArgumentNullException: 'Value cannot be null.
Parameter name: values'... for this mess:
Columns.AddRange(obj.GetType().GetGenericArguments().FirstOrDefault()?.GetProperties().Where(p =>
{
return p.GetCustomAttributes(true).OfType().FirstOrDefault()?.Browsable ?? DefaultBrowsableState;
}).Select(p =>
{
return new ColumnHeader()
{
Name = p.Name,
Text = p.GetCustomAttributes(true).OfType().FirstOrDefault()?.DisplayName ?? p.Name
};
}).ToArray());The thing is, I know what it's trying to do, and the code makes sense to me even though I didn't write it. The LINQ isn't really that bad here. But the error message is just awful. I don't even know where to begin. Time to hand roll the same statement LINQless so I can debug it. So consider this my part 2 in why LINQ is for the birds.
Real programmers use butterflies
-
The underlying issue is that this garbage is a "one-liner". One-liners are darn near impossible to debug. LinQ invites, and even encourages this crap into the code.
As does SQL. If a given statement works, just keep piling on until it doesn't, then post it in Q&A.
It was only in wine that he laid down no limit for himself, but he did not allow himself to be confused by it. ― Confucian Analects: Rules of Confucius about his food
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My crystal ball says your object's type doesn't contain any generic arguments, so you're passing
nulltoAddRange.var genericArguments = obj.GetType().GetGenericArguments();
if (genericArguments.Length != 0)
{
Columns.AddRange(genericArguments[0].GetProperties()
.Where(p => p.GetCustomAttributes(true).OfType<BrowsableAttribute>().FirstOrDefault()?.Browsable ?? DefaultBrowsableState)
.Select(p => new ColumnHeader
{
Name = p.Name,
Text = p.GetCustomAttributes(true).OfType<DisplayNameAttribute>().FirstOrDefault()?.DisplayName ?? p.Name,
});
}Throw in a custom extension method to simplify it slightly:
public static class AttributeExtensions
{
public static TAttribute GetCustomAttribute<TAttribute>(this ICustomAttributeProvider value, bool inherit = true)
where TAttribute : Attribute
{
if (value is null) throw new ArgumentNullException(nameof(value));object\[\] attributes = value.GetCustomAttributes(typeof(TAttribute), inherit); return attributes.Length == 0 ? null : (TAttribute)attributes\[0\]; }}
var genericArguments = obj.GetType().GetGenericArguments();
if (genericArguments.Length != 0)
{
Columns.AddRange(genericArguments[0].GetProperties()
.Where(p => p.GetCustomAttribute<BrowsableAttribute>()?.Browsable ?? DefaultBrowsableState)
.Select(p => new ColumnHeader
{
Name = p.Name,
Text = p.GetCustomAttribute<DisplayNameAttribute>()?.DisplayName ?? p.Name,
});
}
"These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer
Yeah I sorted it out. It was being applied to an instance of the wrong class. The code that's using it is ridiculously complicated, and something small was out of place. This error was the end result. I still think it's suitable for the purposes of this rant. :) Such is life sometimes. I'm working with lots of Other People's Code(TM) at the moment. It's not so much that any one of them is particularly bad, so much as gluing together so many different paradigms is well.. as you can expect. But the main complication of it all is making it designable so my client can open it up in visual studio and tweak it, because he likes to be able to. He can code some, but I'd prefer he keep his mitts off what i write. I can deal with him using the designer. It works for both of us because he's afraid of my code anyway, and that way he doesn't have to bug me for little changes, but sometimes the code to make it all go properly is nasty.
Real programmers use butterflies
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I love LINQ. Developers have been using it for years now, with great success. Sorry you have found another technology that you hate.
There's a pretty large gulf between not liking something and hating it. If I don't like it, it just means I'll avoid using it, and sometimes complain about it. If I hated it I'd probably actively seek to destroy it somehow, and that would be a fight with Microsoft I'd rather not invest in, especially since it's one I couldn't win.
Real programmers use butterflies
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Looks like it's trying to compete with compiler error messages involving C++ templates. :-D
Robust Services Core | Software Techniques for Lemmings | Articles
The fox knows many things, but the hedgehog knows one big thing.;P There are so many things not to like about C++ templates but I love them anyway. It's shameful, my inconsistencies in this regard. :) I suppose it's because LINQ wasn't part of C# since the beginning, I didn't consider C# and LINQ to be irrevocably linked (pardon the pun) the way I do with C++ and templates. It's part of the language, not a "bag on the side". That probably contributes to the difference in attitude I have toward each. But also a little inconsistency never really bothered me that much.
Real programmers use butterflies
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;P There are so many things not to like about C++ templates but I love them anyway. It's shameful, my inconsistencies in this regard. :) I suppose it's because LINQ wasn't part of C# since the beginning, I didn't consider C# and LINQ to be irrevocably linked (pardon the pun) the way I do with C++ and templates. It's part of the language, not a "bag on the side". That probably contributes to the difference in attitude I have toward each. But also a little inconsistency never really bothered me that much.
Real programmers use butterflies
honey the codewitch wrote:
But also a little inconsistency never really bothered me that much.
A foolish consistency is the hobgoblin of small minds. -- Emerson :)
Freedom is the freedom to say that two plus two make four. If that is granted, all else follows. -- 6079 Smith W.
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Here's my error
System.ArgumentNullException: 'Value cannot be null.
Parameter name: values'... for this mess:
Columns.AddRange(obj.GetType().GetGenericArguments().FirstOrDefault()?.GetProperties().Where(p =>
{
return p.GetCustomAttributes(true).OfType().FirstOrDefault()?.Browsable ?? DefaultBrowsableState;
}).Select(p =>
{
return new ColumnHeader()
{
Name = p.Name,
Text = p.GetCustomAttributes(true).OfType().FirstOrDefault()?.DisplayName ?? p.Name
};
}).ToArray());The thing is, I know what it's trying to do, and the code makes sense to me even though I didn't write it. The LINQ isn't really that bad here. But the error message is just awful. I don't even know where to begin. Time to hand roll the same statement LINQless so I can debug it. So consider this my part 2 in why LINQ is for the birds.
Real programmers use butterflies
I find that adding line breaks makes it a lot easier to read. Remember, you are writing for the next person to touch the code, not the computer. It is missing some Elvis operators, before the Where, the Select, and the ToArray, along with providing a value if the null propagates to the end. Also, you don't need the ToArray() as AddRange takes an IEnumerable<T>.
Columns
.AddRange(
obj.GetType()
.GetGenericArguments()
.FirstOrDefault()?.GetProperties()// need the Elvis operator ?.Where(p => { return p.GetCustomAttributes(true) .OfType() .FirstOrDefault()?.Browsable ?? DefaultBrowsableState; }) // need the Elvis operator ?.Select(p => { return new ColumnHeader() { Name = p.Name, Text = p.GetCustomAttributes(true) .OfType().FirstOrDefault()?.DisplayName ?? p.Name }; }) // don't need ToArray(), but need to provide a non-null value for AddRange() ?? Array.Empty());
"Time flies like an arrow. Fruit flies like a banana."
-
Here's my error
System.ArgumentNullException: 'Value cannot be null.
Parameter name: values'... for this mess:
Columns.AddRange(obj.GetType().GetGenericArguments().FirstOrDefault()?.GetProperties().Where(p =>
{
return p.GetCustomAttributes(true).OfType().FirstOrDefault()?.Browsable ?? DefaultBrowsableState;
}).Select(p =>
{
return new ColumnHeader()
{
Name = p.Name,
Text = p.GetCustomAttributes(true).OfType().FirstOrDefault()?.DisplayName ?? p.Name
};
}).ToArray());The thing is, I know what it's trying to do, and the code makes sense to me even though I didn't write it. The LINQ isn't really that bad here. But the error message is just awful. I don't even know where to begin. Time to hand roll the same statement LINQless so I can debug it. So consider this my part 2 in why LINQ is for the birds.
Real programmers use butterflies
I'm not an expert or even a novice ... (serious) Can't you just "unLINQ" this and find and fix the error and LINQ it up again ?
I'd rather be phishing!
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I'm not an expert or even a novice ... (serious) Can't you just "unLINQ" this and find and fix the error and LINQ it up again ?
I'd rather be phishing!
Yes. But that's my point. To get a reasonable error message out of LINQ the solution is do it without LINQ. meh.
Real programmers use butterflies
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I find that adding line breaks makes it a lot easier to read. Remember, you are writing for the next person to touch the code, not the computer. It is missing some Elvis operators, before the Where, the Select, and the ToArray, along with providing a value if the null propagates to the end. Also, you don't need the ToArray() as AddRange takes an IEnumerable<T>.
Columns
.AddRange(
obj.GetType()
.GetGenericArguments()
.FirstOrDefault()?.GetProperties()// need the Elvis operator ?.Where(p => { return p.GetCustomAttributes(true) .OfType() .FirstOrDefault()?.Browsable ?? DefaultBrowsableState; }) // need the Elvis operator ?.Select(p => { return new ColumnHeader() { Name = p.Name, Text = p.GetCustomAttributes(true) .OfType().FirstOrDefault()?.DisplayName ?? p.Name }; }) // don't need ToArray(), but need to provide a non-null value for AddRange() ?? Array.Empty());
"Time flies like an arrow. Fruit flies like a banana."
In my defense I didn't write that, nor run it through autoformat yet.
Real programmers use butterflies
-
Here's my error
System.ArgumentNullException: 'Value cannot be null.
Parameter name: values'... for this mess:
Columns.AddRange(obj.GetType().GetGenericArguments().FirstOrDefault()?.GetProperties().Where(p =>
{
return p.GetCustomAttributes(true).OfType().FirstOrDefault()?.Browsable ?? DefaultBrowsableState;
}).Select(p =>
{
return new ColumnHeader()
{
Name = p.Name,
Text = p.GetCustomAttributes(true).OfType().FirstOrDefault()?.DisplayName ?? p.Name
};
}).ToArray());The thing is, I know what it's trying to do, and the code makes sense to me even though I didn't write it. The LINQ isn't really that bad here. But the error message is just awful. I don't even know where to begin. Time to hand roll the same statement LINQless so I can debug it. So consider this my part 2 in why LINQ is for the birds.
Real programmers use butterflies
It's not really LINQ's fault, it's the chaining of multiple commands into a single statement and also a little of your own inexperience; given that error message many would know exactly where to look.
-
Here's my error
System.ArgumentNullException: 'Value cannot be null.
Parameter name: values'... for this mess:
Columns.AddRange(obj.GetType().GetGenericArguments().FirstOrDefault()?.GetProperties().Where(p =>
{
return p.GetCustomAttributes(true).OfType().FirstOrDefault()?.Browsable ?? DefaultBrowsableState;
}).Select(p =>
{
return new ColumnHeader()
{
Name = p.Name,
Text = p.GetCustomAttributes(true).OfType().FirstOrDefault()?.DisplayName ?? p.Name
};
}).ToArray());The thing is, I know what it's trying to do, and the code makes sense to me even though I didn't write it. The LINQ isn't really that bad here. But the error message is just awful. I don't even know where to begin. Time to hand roll the same statement LINQless so I can debug it. So consider this my part 2 in why LINQ is for the birds.
Real programmers use butterflies
A couple of possibly interesting bits of feedback, assuming that code comes from here: - Adding it to a WinForms app created with .NET Core 3.1 or .NET 5 and turning on nullable reference types finds 17 potential accidental nulls in the code from that SO post. But the Columns.AddRange call itself isn't one of them because WinForms wasn't built with NRT enabled. So the compiler decides it can't say one way or another if passing a null
valuesargument toAddRangeis okay. - Resharper catches the potential error whether you're using .NET Core/.NET 5 or .NET Framework. It even suggests a fix. The static analysis it's doing must look atAddRangeand notice that the first thing that method does is throw an exception ifvaluesis null. -
I find that adding line breaks makes it a lot easier to read. Remember, you are writing for the next person to touch the code, not the computer. It is missing some Elvis operators, before the Where, the Select, and the ToArray, along with providing a value if the null propagates to the end. Also, you don't need the ToArray() as AddRange takes an IEnumerable<T>.
Columns
.AddRange(
obj.GetType()
.GetGenericArguments()
.FirstOrDefault()?.GetProperties()// need the Elvis operator ?.Where(p => { return p.GetCustomAttributes(true) .OfType() .FirstOrDefault()?.Browsable ?? DefaultBrowsableState; }) // need the Elvis operator ?.Select(p => { return new ColumnHeader() { Name = p.Name, Text = p.GetCustomAttributes(true) .OfType().FirstOrDefault()?.DisplayName ?? p.Name }; }) // don't need ToArray(), but need to provide a non-null value for AddRange() ?? Array.Empty());
"Time flies like an arrow. Fruit flies like a banana."
Matthew Dennis wrote:
I find that adding line breaks makes it a lot easier to read
:thumbsup:
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A couple of possibly interesting bits of feedback, assuming that code comes from here: - Adding it to a WinForms app created with .NET Core 3.1 or .NET 5 and turning on nullable reference types finds 17 potential accidental nulls in the code from that SO post. But the Columns.AddRange call itself isn't one of them because WinForms wasn't built with NRT enabled. So the compiler decides it can't say one way or another if passing a null
valuesargument toAddRangeis okay. - Resharper catches the potential error whether you're using .NET Core/.NET 5 or .NET Framework. It even suggests a fix. The static analysis it's doing must look atAddRangeand notice that the first thing that method does is throw an exception ifvaluesis null.Ryan Peden wrote:
Resharper catches the potential error
Ryan Peden wrote:
It even suggests a fix.
:thumbsup:
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There's a pretty large gulf between not liking something and hating it. If I don't like it, it just means I'll avoid using it, and sometimes complain about it. If I hated it I'd probably actively seek to destroy it somehow, and that would be a fight with Microsoft I'd rather not invest in, especially since it's one I couldn't win.
Real programmers use butterflies
Every technology has its place, For simple filtering and selection Linq is quite fine. But for this I would have used other techniques. (Admittedly mixed with linq)
Wrong is evil and must be defeated. - Jeff Ello
-
A couple of possibly interesting bits of feedback, assuming that code comes from here: - Adding it to a WinForms app created with .NET Core 3.1 or .NET 5 and turning on nullable reference types finds 17 potential accidental nulls in the code from that SO post. But the Columns.AddRange call itself isn't one of them because WinForms wasn't built with NRT enabled. So the compiler decides it can't say one way or another if passing a null
valuesargument toAddRangeis okay. - Resharper catches the potential error whether you're using .NET Core/.NET 5 or .NET Framework. It even suggests a fix. The static analysis it's doing must look atAddRangeand notice that the first thing that method does is throw an exception ifvaluesis null.Sounds like nullable reference types is reason enough in itself to upgrade to .Net 5.
Wrong is evil and must be defeated. - Jeff Ello
-
Yeah I sorted it out. It was being applied to an instance of the wrong class. The code that's using it is ridiculously complicated, and something small was out of place. This error was the end result. I still think it's suitable for the purposes of this rant. :) Such is life sometimes. I'm working with lots of Other People's Code(TM) at the moment. It's not so much that any one of them is particularly bad, so much as gluing together so many different paradigms is well.. as you can expect. But the main complication of it all is making it designable so my client can open it up in visual studio and tweak it, because he likes to be able to. He can code some, but I'd prefer he keep his mitts off what i write. I can deal with him using the designer. It works for both of us because he's afraid of my code anyway, and that way he doesn't have to bug me for little changes, but sometimes the code to make it all go properly is nasty.
Real programmers use butterflies
All this complaining about LINQ and AddRange, a non-LINQ function, was the problem? :laugh: Nothing a good old stack trace couldn't have pointed out by the way :zzz:
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Here's my error
System.ArgumentNullException: 'Value cannot be null.
Parameter name: values'... for this mess:
Columns.AddRange(obj.GetType().GetGenericArguments().FirstOrDefault()?.GetProperties().Where(p =>
{
return p.GetCustomAttributes(true).OfType().FirstOrDefault()?.Browsable ?? DefaultBrowsableState;
}).Select(p =>
{
return new ColumnHeader()
{
Name = p.Name,
Text = p.GetCustomAttributes(true).OfType().FirstOrDefault()?.DisplayName ?? p.Name
};
}).ToArray());The thing is, I know what it's trying to do, and the code makes sense to me even though I didn't write it. The LINQ isn't really that bad here. But the error message is just awful. I don't even know where to begin. Time to hand roll the same statement LINQless so I can debug it. So consider this my part 2 in why LINQ is for the birds.
Real programmers use butterflies
The main challenge of LINQ that you don't like (I believe) is one that is quite difficult to accept (for me too) and for many of us who originally learned imperative programming. The main challenge is that LINQ is a declarative construct within an imperative programming language. You probably know this already. Declarative languages expect you to tell them what you want (not how they should do it). However, how they actually get you want you want is hidden (black box). So when they fail, it is quite difficult to know where / why they failed. With imperative programming you have written the steps to get the thing to do the thing and you know where the problem is. Squirrel From A Different Dimension This may not help but it'll help you understand that even though the animal you are wrestling with looks very much like a normal squirrel, it is actually a squirrel that lives in another dimension and it behaves quite differently. :laugh:
