Archive for category .Net

“The .Net Framework installed on this machine does not meet the minimum required version: 4.5.50709” Visual Studio 2012

I wanted to develop a metro style application using Visual Studio 2012 on Windows 8 and I have already installed the Windows 8 release preview on my laptop! (Dual boot with Windows 7, you can see some screen shots here :)). I was trying to install the Visual Studio 2012 express edition and I have got the following error message! 🙂

I have spent few minutes on the web and found out there are some versions conflict, so we have to choose the correct version with operating system!  ( The latest Visual Studio RTM versions won’t install on Windows 8 Release Preview)

So I need to install either one of the RC versions of Visual Studio OR the 90 day evaluation version of Windows 8 version! I will choose the Microsoft Visual Studio Express 2012 RC for Windows 8!

That’s all guys! Happy Installing..!

References:

http://stackoverflow.com/questions/12027597/installing-visual-studio-ultimate-2012-on-windows-8-release-preview

http://connect.microsoft.com/VisualStudio/feedback/details/742858/the-net-framework-installed-on-this-machine-does-not-meet-the-minimum-required-version-4-5-50421

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Difference between ‘Shadowing’ and ‘Overriding’ (Shadowing vs Overriding) – C#

This is a very quick Tech-Tips..! Actually Shadowing is VB.Net concept, in C# this concept called hiding! We will see this chapter later. 🙂

Shadowing : Creating an entirely new method with the same signature as one in a base class.

Overriding: Redefining an existing method on a base class.

  • Both are used when a derived class inherits from a base class
  • Both redefine one or more of the base class elements in the derived class

If you want to read more regarding this, just follow this MSDN topic.


class A
 {
 public int M1()
 {
 return 1;
 }

 public virtual int M2()
 {
 return 1;
 }
 }

class B : A
 {
 public new int M1()
 {
 return 2;
 }

 public override int M2()
 {
 return 2;
 }
 }

class Program
 {
 static void Main(string[] args)
 {
 B b = new B();
 A a = (A)b;

 Console.WriteLine(a.M1()); //Base Method
 Console.WriteLine(a.M2()); //Override Method
 Console.WriteLine(b.M1());
 Console.WriteLine(b.M2());
 Console.Read();
 }
 }

The output is : 1, 2, 2, 2

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SecurityException was unhandled by user code – VSTA, C#, InfoPath 2007

I got this error, while I was developing a InfoPath form in VSTA (Visual Studio Tools for Applications 2008) . This was my enviornment:

  • Windows 7
  • VSTA 2008
  • InfoPath 2007

Scenario: I was trying to get the user information from Active Directory(AD) and then display in an InfoPath form. Here is the C# code I have written in the VSTA:

public void CTRL1_5_Clicked(object sender, ClickedEventArgs e)
 {
 string strUserName = System.Environment.UserName;

 string xpath2 = "/my:myFields/my:field1";
 XPathNavigator field2 = MainDataSource.CreateNavigator().SelectSingleNode(xpath2, NamespaceManager);
 field2.SetValue(GetOU(strUserName)); //Get Organization Unit(OU) from Acitve Directory(AD)
 }

This is the error message I have got: 😦

Solution: I have fixed this issue in a different situation, just read in my previous post.

Thanks. R./

Happy InfoPathing. 🙂

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InfoPath cannot grant access to these files and settings because the form template is not fully trusted. For a form to run with full trust, it must be installed or digitally signed with a certificate – InfoPath 2007 forms Security Levels

After giving the Full Trust to the Form template (See here), we will be able to preview the InfoPath form and get information from other domains, or access files and settings on a user’s computer. But when we publish InfoPath form on SharePoint and try to access the from then you will be getting this error. 😦

Error:

Details:

Text format of the error:

Form template: file:///C:\Documents%20and%20Settings\RajanihanthV\Desktop\XmlProc\InfoPath\ADInfo.xsn</pre>
The form template is trying to access files and settings on your computer. InfoPath cannot grant access to these files and settings because the form template is not fully trusted. For a form to run with full trust, it must be installed or digitally signed with a certificate.

If we need to access the form from SharePoint, we need to be digitally signed the form even it is fully trusted. This is pretty simple, but we have to do this process after publishing the form on SharePoint only. Here are the steps.

Step 1: Navigate to the Document (form) Library, where your form published

Step 2: Click Settings on the Document Library Settings

Step 3: Advanced Settings

Step 4: Edit Template

Step 5: Click the Form Options on the Tools menu

Step 6: Click Sign this Form Template and create or select certificate, then OK

That’s all. You can try and see. 🙂

This will work only for you (author), If you want give access to all users you have to get the digital signature from 3rd party vendors and signed the form.

Thanks. R./

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Request for the permission of type ‘System.DirectoryServices.DirectoryServicesPermission, System.DirectoryServices, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a’ failed – InfoPath 2007 forms Security Levels

When I was trying to display user information from Active Directory(AD) in an InfoPath form, I have got an error message saying that I don’t have permissions to access the Directory services. 😦

Details of the error message:

Text format of the error:

System.Security.SecurityException
 Request for the permission of type 'System.DirectoryServices.DirectoryServicesPermission, System.DirectoryServices, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' failed.
at Template2.FormCode.GetOU(String username)
at Template2.FormCode.CTRL1_5_Clicked(Object sender, ClickedEventArgs e)
at Microsoft.Office.InfoPath.Internal.ButtonEventHost.OnButtonClick(DocActionEvent pEvent)
at Microsoft.Office.Interop.InfoPath.SemiTrust._ButtonEventSink_SinkHelper.OnClick(DocActionEvent pEvent)

I have faced this kind of security level errors while creating a web parts using Active Directory(AD) and you can read this in my previous post.

Basically InfoPath provides three security levels for forms, they are:

  • Restricted
  • Domain
  • Full Trust

The security levels determine whether a form can access data on other domains, or access files and settings on a user’s computer. If you need more info about this, just click here.

When we design/create an InfoPath form, the minimum trust level will be assigned in-default and which is not enough to access the Directory Services. So we need to change the trust level to access the information.  These are the simple steps to change the Trust Levels in InfoPath,

Step 1: Open the Form template in Design Mode

Step 2: Click the Form Options on the Tools menu

Step 3: You will be getting the following window and the security levels automatically determined

Step 4: Unchecked the check box, give the permissions to ‘Full Trust’ and then click OK

That’s all, you can access the Directory Services programmatically and display in your InfoPath form.  Sometimes you will be getting another error after fixing this (probably after publishing to SharePoint), to solve this problem we just need to specify the digitally signed certificate for this form. Check out the error message here.

Thanks. R./

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Difference between ‘ref’ and ‘out’ parameters (ref vs out) – C#

  • Both are treated differently @ runtime but same in the compile time, so can’t be overloaded.
  • Both are passed by references except ‘ref’ requires that the variable to be initialized before passed.

ref:

class Program
 {
 static void M1(out int i)
 {
 i = 1;
 i += 1;
 }

static void Main(string[] args)
 {
 int j; //Not assigned
 M1(out j);
 Console.Write(j);
 Console.Read();
 }
 }
}

The output is : 2

out:

class Program
 {
 static void M1(ref int i)
 {
 i = 1;
 i += 1;
 }

 static void Main(string[] args)
 {
 int j=0; //Assigned
 M1(ref j);
 Console.Write(j);
 Console.Read();
 }
}

The output is same: 2, but we have to assigned the variable before used otherwise we will get an error.

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‘Microsoft.SharePoint.Client.Form’ does not contain a constructor that takes 0 arguments – SharePoint 2010 Client Object Model

To fix this issue, just click here. Thanks, R../

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