explain what is the difference between IsDbnull() method and convert.isDbNull(). Can you explain how do we implement both these methods with the of examples
View 1 RepliesI have the following code:
Dim getProspect = (From p In dbContext.IRF_Prospects _
Where p.url = prospect_url _
Select p).FirstOrDefault
[Code]....
When I execute it, it throws an object reference not set to an instance of an object error on getProspect.user_id. Why is it doing this? Shouldn't the fact that I'm verifying it exists using IsDBNull first keep this from happening?
I am getting a datarow from my dataset and some columns can be NULL.So I am trying to check for this using the IsDBNull function, but it just won't work. I have tried almost every possible combination. Can someone please explain to me how to use this properly?ser is a datarow and GUID is a column with data type: unique indentifier (so a Sytem.Guid)
user.GUID.Equals(DBNull.Value) Then .GUID = System.Guid.NewGuid
I tried using above, IsDBNull(GUID), guid = dbnull.value, guid is dbnull.value etc etc I am just getting this error: The specified Cast is not valid.
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I just need to know what is the slight difference between them so I know which one to use everytime.
View 5 RepliesWhat's the difference between using the in out attributes in a interop method call such as SomeWIN32APICall(<[In],Out> Byval SomeVariable as SomeType) Vs SomeWin32APICall(ByRef SomeVariable as SomeType)? When I use the latter my app crashes.Edit: Fixed Typo
View 1 RepliesDo you really need this keyword to overload methods? What is the difference between using the overloads keyword vs. just having different method signatures?
View 5 RepliesC#: Difference between int.Parse( ) & Convert.ToInt32( ) ?And Which one we have to use on what cases--
View 15 RepliesI am trying to convert a method in C# to VB, but am finding it impossible.the C# code is
[Code]...
I desperately need this VB.NET code converted to PHP.This is the Instructions I received:To test your encryption, encrypt the following word with these keys and check if you get the same result:
Text to encrypt: MyPassword
Salt key: *&^%$#@!
PBE Key: FWV70700[code].....
I have the following in C#: public static void StartAnimation(UIElement animatableElement, DependencyProperty dependencyProperty, double toValue, double animationDurationSeconds, EventHandler completedEvent)
[Code]...
public static string CalculateSHA1(string text, Encoding enc)
{
byte[] buffer = enc.GetBytes(text);
SHA1CryptoServiceProvider cryptoTransformSHA1 = new SHA1CryptoServiceProvider();
[code]....
VStudio keeps yelling at me for just what I have so far most specifically the bracket at the end of Byte?:
Private Sub CalculateSHA1(ByVal text As String, ByVal enc As Encoding)
Dim buffer As Byte[] = enc.GetBytes(text);
End Sub
I've been trying to figure out how to do this for some time now and keep coming up short, so I'm hoping to get some good suggestions.
I'm making an application that will allow the user to add some labels during runtime, edit their text, and then 'build' the designer that would output code for a scripting language.
The people using this app are creating the scripts using Notepad++ at the moment, but aren't developers in any way and would like an easier, point and click method.[code]...
i want to extend the integer class to a method that increments current integer value by 2. I create a console application and a second module which contains the extension method.
Imports System.Runtime.CompilerServices
Module StringExtensions
<Extension()>
[code]....
and everything works fine. The extension method module can be imported to any other project (Project-->add existing item --> select the vb file that contains the extension method module) and works fine too. But the code is accessible to other users. Is there a method to convert the extension method module to a dll and adding it to other projects as a reference. I tried to do it with creating a class project and pasting the code of the extension method module and compile the dll and then added it as reference to another project and imported the class with the keyword imports, but it didn't work.
Is there a Visual Basic.NET method that can convert method parameters into an array?[code]...
View 2 RepliesHow would you convert this to VB (using .NET 4.0 / VS2010) ?
bw.DoWork += (o, args) =>
{
Code Here
};
I thought maybe like this:
AddHandler bw.DoWork,
Function(o, args)[code]....
But it says Function does not return a value on all code paths.
I have some files in vb.net that have "Option Strict Off" to allow for bad programming. When I convert to c# I use "dynamic" until I come back and fix problems, and this works in all cases But now I have this code:
Public Class ContractResults
'Big class definition
Public Shared Sub CleanCache()
[code].....
And in a file with Option Strict Off:
Public Sub VerifyResults(result as Object)
'Here, result is normally ContractResults
'first it check for that then call this:
result.CleanCache()
End Sub
In c# I use "dynamic", but a runtime error pops up when I call "static" method with dynamic reference. In vb.net, I can called "shared" sub from instance, but in c# this is not allowed
Exception:
"Microsoft.CSharp.RuntimeBinder.RuntimeBinderException"
"Member 'ContractTypes.ContractResults.CleanCache()' cannot be accessed with an instance reference; qualify it with a type name instead"
It seems I must convert code to use actual type, but then this means much rewriting of more parts. Is anyone able to show another way?I want to make sure you do not think I can use (result as ContractResults).CleanCache();Because all types that may be passed in have "CleanCache()" method, but do not inherits from anything the same other than "Object". There are many types (30!) that have this "static" method and so that is why it uses Option Strict Off?
I am stuck trying to convert code that works in C to VB. The C code is:internal IEnumerable<GraphicsBase> Selection
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I have read the stuff about how this has to be done in VB using GetEnumerator method, but I just can't seem to get it to work.
Consider a MyForm class that contains a shadowed implementation of Show(). It also contains a CreateForm() method, which accepts an instance of the form and calls the shadowed sub:
[Code]....
I decided to to convert my excel macro in a exe file using visual studio 2010. In excel macro method find is present like this:
[Code]...
Does calling the Dispose method on a Windows.Forms.Timer call it's Stop method? Or should I stop the timer before I dispose it?
View 5 RepliesI have a large problem with inheritance in vb.net. The problem is the following:
I have 2 forms => frmBase and frmChild
In frmBase i want to create a method Called StartWorking() and i want frmChild to inherit this method.
But here is the tricky thing: when frmChild.StartWorking is called i would like the following => without calling MyBase.StartWorking()
I want frmBase.StartWorking() to be executed first and after a test in frmBase.StartWorking if blnValue is true then frmChild.StartWorking has to be activated. if blnValue is false that frmChild.StartWorking cannot be activated.
I have nine pictures that I need to animate -I need to use the ToString method and a counter to concatenate a file name into a string variable from the Image.FromFile method. Once the counter reaches its maximum value, and the last picture is displayed, the counter should be reset to zero or one depending on how the first image file has been name. Also a static counter variable should be incremented in the time routine. what I have so far -- I know what I have to do; however, I just do not know how to code this properly.. Right now I have this going thru a button procedure but it needs to go through a timer.
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Write an overload for every numeric type or if possible constrain a generic extension method to just numeric types.
View 2 RepliesI will try to explain what I need.Let's say that I have a class like this:
Public Class Example1 Public Sub ToBeCalled()
[Code]...
When I am loading an Assembly dynamically, then calling a method from it, I appear to be getting the method from Assembly executing before the code in the method that is calling it.It does not appear to be executing in a Serial manner as I would expect. Can anyone shine some light on why this might be happening. Below is some code to illustrate what I am seeing, the code from the some.dll assembly calls a method named PerformLookup. For testing I put a similar MessageBox type output with "PerformLookup Time: " as the text. What I end up seeing is:
First: "PerformLookup Time: 40:842"
Second: "initIndex Time: 45:873"
Imports System
[code].....
Why does my the declaration of my string in the code result in the following error? Is there a workaround?
Code:
<script runat="server">
Protected Sub form1_Load(sender As Object, e As System.EventArgs)
Dim x As String = "</script>"
[code]....
Error: Statement cannot appear within a method body. End of method assumed.
Note: The following page did not fix my issue and instead resulted in the string </script> being output in my page. ( VB.NET hates </script> tag in string literal )
I am not sure whether this is a trick question?One of the object i have has 2 boolean properties, Standing and Sitting.I have a class called student with the 2 methods stated below- Am I coorrect is assuming that the first method draw() is affected by the standing property AND not the second method?Also the way it affects is that it draws an image when the the stugent is standing?
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What's the equivalent method in .NET of the Picture1.Scale (0,0)-(10,10) method in 6.0?
View 2 RepliesLet's say I have a page Test.aspx along with test.aspx.vb.Test.aspx.vb contains a class name "TestClass". In that class I have method1(), method2() and method3()I need to be able to call one of those methods, but I can't hard code it, the method to be executed comes from a string.
I can't do
Select Case StringContainingTheNameOfTheDesiredMethod
Case "Method1"
[code]...
Extension methods are useful for types that you don't own and can't/don't want to derive from and extend (e.g. reference types and interfaces). Obviously, interfaces should be kept as short and to-the-point as possible, so extension methods for interfaces are particularly useful (e.g. LINQ).For classes, especially classes that you own, they're still useful - but I'm wondering how you determine what should be an extension method or what should be a method in the class itself.Personally, every time I think about it, I keep going round in circles with the following thoughts:If it's useful enough, it should be in the class.It's not part of the core responsibility of the class, it should be an extension method - but if it's useful enough, surely it should be the responsibility of the class...
View 3 Replies