I have a problem with a code snippet I tried to play with, and since I am new to dart I don't really understand the error message. Can somebody explain to me why the error message says
The constructor returns type 'dynamic' that isn't of expected type
'widget'.
and how to fix it?
The class MaterialList doesn't exist. It looks like maybe you meant TwoLevelList, which is deprecated. You should try ListView instead.
If you have other import statements try to use alias as some libraries may be the reason for conflict.
Example: import 'package:html/parser.dart' as parser;
Related
The instructor in the C++ course I'm following used this code here, and I copied it exactly:Code the course instructor used
But I get this error. Not sure what to do. I know that the instructor is doing this in 4.27 and I'm doing it in 5.1. Did something change between those two versions that may have caused this error? How to I get around it?
The error I'm receiving
Here's my whole function for reference:
Whole function
I also faced this problem. Here is the workaround.
For UE5.1 you need to write this in your file, #include "Engine/DamageEvents.h".
This statement:
new NumberFormat("#.##").format(12.33)
throws this error:
"Class 'double' has no instance method '&'"
Is it a bug or am I doing something wrong?
This is probably a known issue: https://code.google.com/p/dart/issues/detail?id=9215
I guess you don't need to worry about it, it should be fixed soon.
I just splited a project in a few libraries.
And I have the strange error in the title.
I can't explain myself why it is the case.
Also, this error used to show up only in FSI.exe
I thought it was because of pb with loading dll in fsi but there is more to this.
It might be a stupid error (probably is..) but if anyone encoutered this sybillin error message before and knows what happens, I'd be glad to hear it.
UPDATE
I thought it was namespace issues, but it is not.
This issue is very odd. Please ignore it if you did not experienced it. I am still trying to pinpoint the exact origin.
Without more information it's hard to know for sure. One way this could happen is if you end up redefining a type in FSI without redefining some things that depend on it. Then those things expect the old version of the type, but you end up creating instances of the new version, which are not compatible. For instance, given this code:
type MyType<'a>() = class end
let myFun (_:MyType<int>) = 0
let result = myFun (MyType())
If I send the first two lines to FSI, then the first line again by itself, and then the third line, I get something similar to your error message. The solution is to re-evaluate all dependent definitions.
I'm getting an error when I'm trying to replace a GoTo in a while loop with a Continue, but whenever I do I get an error reading "Statement expected, but expression of type 'Boolean' found". Is continue a keyword not in Delphi 6? Does the error message mean something else?
Thanks.
It is in Delphi 5, so I would assume it is in Delphi 6.
There must be something else going on in your code, but without posting it, it's impossible to tell.
The error message means that somebody gave a variable the same name as the keyword and Delphi is using that instead of the keyword. Find the variable and try renaming it.
When using the following line code in Delphi 2010, a'm getting an "Access Violation" error, but the same code working fine in VC++.
The Delphi 2010 code is
var
hMyInf : HINF;
begin
hMyInf := SetupOpenInfFile('.\\DIGIMHID.INF','Mouse', INF_STYLE_WIN4,Nil);
The VC++ code is
hMyInf = SetupOpenInfFile(".\\DigimHID.inf", "Mouse", INF_STYLE_WIN4, NULL);
Please help me to solve this issue.
Thanks All.
Call LoadSetupAPI before using any methods in the SetupAPI.pas
Edit, to provide some background: As simultaneously wrote by David in his answer and by me in my comment, the error is probably caused by calling an uninitialized method pointer. For me the first tip was the error message, an Access Violation: If the equivalent of an Access Violation came from Windows itself, it'd be called a Runtime Error 216. The code is very simple, only uses constants and a method call. Constants can't generate AV's so the error had to come from the method itself, or from calling the method.
Since the Delphi declaration supplied showed a "function type", I suspected SetupOpenInfFile is actually an method pointer, not an import method. Those pointers need to somehow be initialized. Searching SetupAPI.pas (thanks google for providing a link, because I don't use JEDI libraries) I quickly found that it's being assigned from LoadSetupAPI. My first thought: isn't LoadSetupAPI called from the initialization section? It's not, so it needs to be called from code. Problem solved.
Your filename is wrong in the Delphi version. You don't escape \ in Delphi, a single one will do. But that wouldn't lead to an access violation.
My guess is that your GetProcAddress call is failing. But that is a guess. I'd like to see more code and the full error message.
EDIT
It seems that we were on the right track. Cosmin's answer will solve the problem for you. An alternative would be to switch to inplicit linking by removing the definition of the condition SETUPAPI_LINKONREQUEST in SetupApi.pas.