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string.IsNullOrEmpty vs string = '' in Visual Basic


string.IsNullOrEmpty vs string = '' in Visual Basic

By : noome
Date : November 18 2020, 01:01 AM
I hope this helps you . The String.IsNullOrEmpty method checks for both null and empty fields, while string=="" only checks for empty fields.
If a string is not defined, it will be null by default. Therefore, it is a better idea to use IsNullOrEmpty.
code :


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Visual Basic Value of type '1-dimensional array of String' cannot be converted to 'String

Visual Basic Value of type '1-dimensional array of String' cannot be converted to 'String


By : DonM
Date : March 29 2020, 07:55 AM
I think the issue was by ths following , The System.IO.Directory.GetDirectories(Backup) returns an array of strings.
You probably need to change it to this:
code :
'This will insert each value returned from GetDirectories'
For Each Dir as String in System.IO.Directory.GetDirectories(Backup)
  Label4.text &= Dir & VbCrLF
Next

'Alternatively, if you just need the first result:'
Label4.text = System.IO.Directory.GetDirectories(0)
Creating dynamic Linq Expression using String.IsNullOrEmpty(string) and Nhibernate

Creating dynamic Linq Expression using String.IsNullOrEmpty(string) and Nhibernate


By : umashankertiwari
Date : March 29 2020, 07:55 AM
Hope that helps I am simply not sure what you are trying to achieve here. The dynamic expression query language is already there: it is the built-in LINQ provider. But let's try to give you more information about its implementation.
When the built-in Linq provider recieves the query, represented by expressions tree, a visitor pattern is used for its conversion into the SQL (with a middle HQL step). One powerful part is the method inspection represented by interface IHqlGeneratorForMethod
code :
public interface IHqlGeneratorForMethod
{
    IEnumerable<MethodInfo> SupportedMethods { get; }
    HqlTreeNode BuildHql(MethodInfo method, Expression targetObject
          , ReadOnlyCollection<Expression> arguments, HqlTreeBuilder treeBuilder
          , IHqlExpressionVisitor visitor);
}
DictionaryItemGenerator
DictionaryContainsKeyGenerator
EqualsGenerator
BoolEqualsGenerator
MathGenerator
AnyHqlGenerator
AllHqlGenerator
MinHqlGenerator
MaxHqlGenerator
CollectionContainsGenerator
HqlGeneratorForExtensionMethod
StartsWithGenerator // StartsWith
EndsWithGenerator   // EndsWith
ContainsGenerator   // Contains
ToLowerGenerator
ToUpperGenerator
SubStringGenerator
IndexOfGenerator
ReplaceGenerator
TrimGenerator
.Where(x => x.MyProperty == null || x.MyProperty == "")
Is there any point in having default form String.IsNullOrEmpty(str) instead of str.IsNullOrEmpty()?

Is there any point in having default form String.IsNullOrEmpty(str) instead of str.IsNullOrEmpty()?


By : Melrose06
Date : March 29 2020, 07:55 AM
will help you The reason why it isn't implemented as an extension method (which, at the end of the day, is still just a static method) is historic - Extension methods didn't exist until C# 3 / VB 9 - over half a decade after String.IsNullOrEmpty debuted in .NET 1.0.
Extension methods that don't throw a NullReferenceException when their first parameter is null are actually very confusing to reason about - since that gives them behaviour unlike normal instance methods.
Why in Visual Studio 2015 string.IsNullOrEmpty is better than String.IsNullOrEmpty?

Why in Visual Studio 2015 string.IsNullOrEmpty is better than String.IsNullOrEmpty?


By : Alex B
Date : March 29 2020, 07:55 AM
it should still fix some issue I have been writing String.IsNullOrEmpty for years, and in Visual Studio 2015, the IDE suggests to refactor it into string.IsNullEmpty, Why? what would you do? , It's due to a "Code Style" option, under:
string.IsNullOrEmpty & string.IsNullOrWhiteSpace return false for empty string

string.IsNullOrEmpty & string.IsNullOrWhiteSpace return false for empty string


By : user3663179
Date : March 29 2020, 07:55 AM
I hope this helps you . As stated in my comment, in that screenshot you can see that trimmedSentence.Length is 1, therefore it's not empty, and its contents is definitely not a standard space. If the string appears empty, it's because it has one of those so-called invisible characters. To check what your string has, you can directly access that character by doing trimmedSentence[0].
If that character will appear often, you might want to consider doing this:
code :
string trimmedSentence = sentence.Trim().Replace("<this special character>", "");
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