Public Enum Fruit
Red_Apple = 1
Oranges
Ripe_Banana
End Enum
Private Sub InitCombosRegular()
[Code]...
Why does the Ctype work and the Directcast does not with the same syntax? Yet if I cast the selectedValue to an int before I DirectCast, then it works
I am an experienced C/C++/C# programmer who has just gotten into VB.NET. I generally use CType (and CInt, CBool, CStr) for casts because it is less characters and was the first way of casting which I was exposed to, but I am aware of DirectCast and TryCast as well. Simply, are there any differences (effect of cast, performance, etc.) between DirectCast and CType? I understand the idea of TryCast.
View 2 RepliesI turned option strict on, wich gave me some errors. The errors are quite easy to fix, but it seems like there are several ways of doing things. [code] 'previoustime' is declared as a TimeSpan, and the column "sluttid" is defined as a TimeSpan-column.Now, as far as I know, there are two ways of solving this; using CType and using DirectCast, like this: [code]
View 4 RepliesDoes DirectCast, ctype, etc., are common function? Why it return type, and how do I used it? Is there others function where I need learn to be dot net expert?
View 3 RepliesEver since I moved from VB6 to VB.NET somewhere in 2005, I've been using CType to do casting from one data type to another. I do this because it is simply faster to type, used to exist in VB6 and I do not know why I have to be using DirectCast if there is apparently no difference between them.I use TryCast once in a while because I understand that sometimes casting can fail. I however cannot get the difference between CType and DirectCast.
View 3 Repliesin terms of performance (speed), does directcast beat ctype?
View 6 RepliesWe have legacy character codes that we want to store as numbers in a new system. To increase readibility and general understanding in the code for devs making the migration, I want to do Enums like this..
[Code]...
With this setup, the code will be readable (imagine If Record.Status = Status.Open), and yet the values will be stored in the database as small numbers so it will be efficient. However... I am a VB.NET guy, but everybody wants to code in C#, so I need this sort of structure in C#.After Googling, I discovered the the general .NET equivalent of AscW is Convert.ToInt32("C"). When I try to use that statement in an enum, I get the compiler error "Constant Expression Required".
I thought that enums in VB and C# where the same or at least very similar. Then today I stumbled across a bug in our VB code. The following VB code compiles and runs with no issues:
Enum Cars
Subaru
Volvo
End Enum
[code]....
Why does the VB version not catch the type mismatch? Are enum in VB and C# different?
Does C# have an equivalent to VB.Net's DirectCast?I am aware that it has () casts and the 'as' keyword, but those line up to CType and TryCast.To be clear, these keywords do the following;CType/() casts: If it is already the correct type, cast it, otherwise look for a type converter and invoke it. If no type converter is found, throw an InvalidCastException.
TryCast/"as" keyword: If it is the correct type, cast it, otherwise return null.DirectCast: If it is the correct type, cast it, otherwise throw an InvalidCastException.
EDIT: After I have spelled out the above, some people have still responded that () is equivalent, so I will expand further upon why this is not true.
DirectCast only allows for either Narrowing or Widening conversions on inheritance tree, it does not support conversions across different branches like () does.ie: C#, this compiles and runs:
//This code uses a type converter to go across an inheritance tree
double d = 10;
int i = (int)d;
[code]....
i am using code to the value textbox2.text in the report and using the code like below [code]the textbox2 take various values in run time but when i run the code it display only the final value intermediated values are not displayed the whole situation is as follows.[code]
View 1 RepliesI have a very simple problem where I have a MyList As List(Of MyBaseClass) but and a couple of MySub(ByVal Dummy As MyDerivedClassA)/MySub(ByVal Dummy As MyDerivedClassB). So I want to do the following ...
For Each MyInstance As MyBaseClass In MyList
MySub(DirectCast(MyInstance, MyInstance.GetType())
...
[code].....
I learned how to use DirectCast over the last few days and it's really helped me. However, I have a similar issue, instead of textboxes I am looking at variables that are referenced in the class.To bring you all up to speed, I have four variables, a Boolean that dictates each of the 4 players I have playing my game. [code] I would assume it'd work similar to DirectCast but I am unsure. What I came up with caused errors: [code]
View 14 RepliesI have 15 textboxes named MissionT1-15Is there a simple way to set all of their text to "Mission"?
missionT1.text="Mission"but for all of them with a loop?I saw something with directcast but wasn't able to make it work.
Possible Duplicate: Why use TryCast instead of Directcast ? I want to know about the trycast and direct cast in vb.net. What is the difference between them?
View 2 RepliesUntil asking a question on here I never considered (enums) to be a "bad thing." For those out there that consider them not to be best practice, what are some approachs/patterns for avoiding their use in code?
Edit:
public Enum SomeStatus
Approved = 1
Denied = 2
Pending =3
end Enum
I have an enum and a usercontrol, both in the same assembly (a plain .NET 4 web site). In the Constants class:public Enum CrudOperations Add Edit Delete. This controls the columns in a GridView on a UserControl via a property on the UserControl
[Code]...
In C#, I've specified the columns to show with markup as Mode="Edit,Delete", but in VB.NET, this does nothing. The only way I can get anything to show is with the codebehind, but if on the containing page I use userGrid.Mode = CrudOperations.Edit And CrudOperations.Delete, I get all the columns (there's also a delete column), but userGrid.Mode = CrudOperations.Edit Or CrudOperations.Delete shows nothing.
I have a public property, "Status" that is an enum. I have a setter method that changes the status and raises the PropertyChanged event. However, the WinForms user interface is not properly updating. I'm pretty sure it's because Status is an enum. Although I was thinking enum was a reference type but I guess it's a value type. Does INotifyPropertyChanged work the same with reference and value types?
[Code]...
What is the difference between DirectCast and TryCast? Can someone illustrate it in very simple words along with an example?
View 5 RepliesI have an SQL query that gets a max value so that I can decide the next value to use in an ID field. The code works fine when there's a matching result, but if the query returns Null, it throws a Specified Cast is Invalid error.This is the code I'm using:
LastID = DirectCast(SQLQuery.ExecuteScalar(), Integer)
What would be the proper way to check for a null value?
I suspect this is going to be one of those cases where within 2 minutes of posting myquestion, I finally hit upon the right combination of terms in Google to find what I'm looking for...
I usually avoid VB's built-in conversion functions (CStr, CDate, CBool, CInt, etc.) unless I need to do an actual conversion. If I'm just casting, say from an object to a string, I normally use either DirectCast or TryCast, under the assumption that CStr, etc., are doing some extra stuff I don't need. But sometimes the DirectCast syntax is a little cumbersome, as in the following example.[code]SqlDataReader.Item returns an Object, which needs to be cast to a String. CStr is easier to read, type, and explain (IMO). My question is, does it matter which one I use? Should I just go with CStr (and CDate and CBool, etc.) and not worry about the extra work I assume those functions are doing? Is there any other downside to using these functions?
View 3 RepliesI was wondering if there was anyway for me to get the string value of a point variable so that I can compare it. I tried to do something like:
DirectCast("point" & number, Point).ToString
I work for a web hosting company and was handed a VB script which I apparently have to compile with some updated settings by 1 of our clients who knows less about it than I do. But when trying to compile the code I receive an error "'Enums.NoticeType' is not defined". As expected I haven't a clue. Am I missing some of the code, or do I have to add some libraries in my Visual Basic 2008 Express Edition? I have pasted the line of code below. If requested I can provide the whole script.
Code:
Public Function UpdateNotices(ByVal intNoticeID As Integer,
ByVal strNoticeTitle As String, ByVal dtDateFrom As Date, ByVal dtDateTo
As Date, ByVal intTypeID As Enums.NoticeType, ByVal boolPrimaryItem As
Boolean, ByVal boolActive As Boolean) As Int32
I have a solution with multiple projects, some of the projects are written in VB, some in C#. I am wondering if there's a way to use interfaces and/or enums written in VB in C# classes? My C# code below doesn't compile, however I am able to see the interface in intellisense.
[Code]...
P.S It's a console/service application, not ASP.Net (where I know it's doable).UPD: Sorry guys, was missing a reference to the project with the interface. It's fixed now. I think the thing that in VB projects references are done slightly different than in C# confused me.
I have a base class with the the following enum and property:
[Code]...
First off, how do I do this - is it by simply overloading it? And secondly will my original property pick up the new enum automatically when using the derived class or will I need to overload that too?
We have a common component in our source which contains all the enums (approx 300!) for a very large application.Is there any way, using either C# or VB.NET, to iterate through all of them in order to perform an action on each one?
How to iterate all "public string" properties in a .net class is almost relevant but the enums I am dealing with are a mix of types.
I'm using LuaInterface for .NET to create Windows Forms objects. This works pretty good except for one thing:I want to use the Anchor property of Control to make them resize automatically. If I only set one of the Anchors (e.g. only AnchorStyles.Top), it works, but this doesn't really make sense. I have to set more than one Anchor, which is done by combining them with "bit-wise or" (or by just adding them numerically).
In VB.Net both works:
Dim myLabel As New Label()
myLabel.Anchor = AnchorStyles.Top[code]....
which is in a sense correct as "LuaInterface treats enumeration values as fields of the corresponding enumeration typ" (says LuaInterface: Scripting the .NET CLR with Lua).It is also not possible to assign the value as a number:
myLabel.Anchor = 15 -- 15 = 8 + 4 + 2 + 1 = Top+Left+Right+Bottom
This time, the error message is rather unspecific:
LuaInterface.LuaException: function
Is there a possibility to typecast the number to the correct enumeration type in Lua?
What would the folowing VB.NET enum definition look like in C#? [code]
View 7 RepliesIs it guaranteed that the numeric values for an Enum with only uninitialized values start at zero and increment by one in the order defined?
View 2 RepliesI want to add a setting that uses an enum defined in form1.vb. All the research I've done suggests support for enum type settings is built-in and handled automatically by the VS IDE ... I assume this means it's as easy as defining font or color settings. However, I'm not having much. Are any of you gurus aware of how to set up an enum setting via the Project Settings UI?
View 8 RepliesI realize this is probably trivial, but for some reason I'm not sure how to pull it off. Say I have the following enum:
Public Enum FlagType
Docs
Email
[Code]....
How do I then at runtime determine which flags where set for flags? In this example, it should be Docs and Email.