How to: Detect Whether the .NET Framework 3.5 Is Installed

  • Article

Before administrators can deploy Windows Presentation Foundation (WPF) applications on a system that targets the .NET Framework 3.5, they must first confirm that the .NET Framework 3.5 runtime is present. This topic provides a script written in HTML/JavaScript that administrators can use to determine whether the .NET Framework 3.5 is present on a system.

Note

For more detailed information on installing, deploying, and detecting the .NET Framework, see Where to Obtain the .NET Framework Redistributable Package.

Example

When the .NET Framework 3.5 is installed, the MSI adds ".NET CLR" and the version number to the UserAgent string. The following example shows a script embedded in a simple HTML page. The script searches the UserAgent string to determine whether the .NET Framework 3.5 is installed, and displays a status message on the results of the search.

Note

This script is designed for Internet Explorer. Other browsers may not include .NET CLR information in the UserAgent string.

<HTML>
  <HEAD>
    <TITLE>Test for the .NET Framework 3.5</TITLE>
    <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=utf-8" />
    <SCRIPT LANGUAGE="JavaScript">
    <!--
    var dotNETRuntimeVersion = "3.5.0.0";
    
    function window::onload()
    {
      if (HasRuntimeVersion(dotNETRuntimeVersion))
      {
        result.innerText = 
          "This machine has the correct version of the .NET Framework 3.5."
      } 
      else
      {
        result.innerText = 
          "This machine does not have the correct version of the .NET Framework 3.5." +
          " The required version is v" + dotNETRuntimeVersion + ".";
      }
      result.innerText += "\n\nThis machine's userAgent string is: " + 
        navigator.userAgent + ".";
    }
    
    //
    // Retrieve the version from the user agent string and 
    // compare with the specified version.
    //
    function HasRuntimeVersion(versionToCheck)
    {
      var userAgentString = 
        navigator.userAgent.match(/.NET CLR [0-9.]+/g);

      if (userAgentString != null)
      {
        var i;

        for (i = 0; i < userAgentString.length; ++i)
        {
          if (CompareVersions(GetVersion(versionToCheck), 
            GetVersion(userAgentString[i])) <= 0)
            return true;
        }
      }

      return false;
    }

    //
    // Extract the numeric part of the version string.
    //
    function GetVersion(versionString)
    {
      var numericString = 
        versionString.match(/([0-9]+)\.([0-9]+)\.([0-9]+)/i);
      return numericString.slice(1);
    }

    //
    // Compare the 2 version strings by converting them to numeric format.
    //
    function CompareVersions(version1, version2)
    {
      for (i = 0; i < version1.length; ++i)
      {
        var number1 = new Number(version1[i]);
        var number2 = new Number(version2[i]);

        if (number1 < number2)
          return -1;

        if (number1 > number2)
          return 1;
      }

      return 0;
    }
    
    -->
    </SCRIPT>
  </HEAD>
  
  <BODY>
    <div id="result" />
  </BODY>
</HTML>

If the search for the ".NET CLR " version is successful, the following type of status message appears:

This machine has the correct version of the .NET Framework 3.5.

This machine's userAgent string is: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0; SLCC1; .NET CLR 2.0.50727; .NET CLR 1.1.4322; InfoPath.2; .NET CLR 3.0.590; .NET CLR 3.5.20726; MS-RTC LM 8).

Otherwise, the following type of status message appears:

This machine does not have the correct version of the .NET Framework 3.5. The required version is v3.5.0.0.

This machine's userAgent string is: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0; SLCC1; .NET CLR 2.0.50727; .NET CLR 1.1.4322; InfoPath.2; .NET CLR 3.0.590; MS-RTC LM 8).

See Also

Concepts

How to: Detect Whether the .NET Framework 3.0 Is Installed

Change History

Date

History

Reason

November 2010

Added Note about script and Internet Explorer.

Customer feedback.