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AccessDbProviderSample02 Code Sample

The following code shows the implementation of the Windows PowerShell provider described in Creating a Windows PowerShell Drive Provider. This implementation creates a path, makes a connection to an Access database, and then removes the drive.

Note

You can download the C# source file (AccessDBSampleProvider02.cs) for this provider using the Microsoft Windows Software Development Kit for Windows Vista and Microsoft .NET Framework 3.0 Runtime Components. For download instructions, see How to Install Windows PowerShell and Download the Windows PowerShell SDK. The downloaded source files are available in the <PowerShell Samples> directory. For more information about other Windows PowerShell provider implementations, see Designing Your Windows PowerShell Provider.

Code Sample

using System;
using System.IO;
using System.Data;
using System.Data.Odbc;
using System.Management.Automation;
using System.Management.Automation.Provider;
using System.ComponentModel;

namespace Microsoft.Samples.PowerShell.Providers
{
   #region AccessDBProvider

    /// <summary>
   /// A PowerShell Provider which acts upon a access data store.
   /// </summary>
   /// <remarks>
   /// This example only demonstrates the drive overrides
   /// </remarks>
   [CmdletProvider("AccessDB", ProviderCapabilities.None)]
   public class AccessDBProvider : DriveCmdletProvider
   {
       #region Drive Manipulation

       /// <summary>
       /// Create a new drive.  Create a connection to the database file and set
       /// the Connection property in the PSDriveInfo.
       /// </summary>
       /// <param name="drive">
       /// Information describing the drive to add.
       /// </param>
       /// <returns>The added drive.</returns>
       protected override PSDriveInfo NewDrive(PSDriveInfo drive)
       {
           // check if drive object is null
           if (drive == null)
           {
               WriteError(new ErrorRecord(
                   new ArgumentNullException("drive"), 
                   "NullDrive",
                   ErrorCategory.InvalidArgument, 
                   null)
               );
            
               return null;
           }
        
           // check if drive root is not null or empty
           // and if its an existing file
           if (String.IsNullOrEmpty(drive.Root) || (File.Exists(drive.Root) == false))
           {
               WriteError(new ErrorRecord(
                   new ArgumentException("drive.Root"), 
                   "NoRoot",
                   ErrorCategory.InvalidArgument, 
                   drive)
               );
 
               return null;
           }

           // create a new drive and create an ODBC connection to the new drive
           AccessDBPSDriveInfo accessDBPSDriveInfo = new AccessDBPSDriveInfo(drive);

           OdbcConnectionStringBuilder builder = new OdbcConnectionStringBuilder();

           builder.Driver = "Microsoft Access Driver (*.mdb)";
           builder.Add("DBQ", drive.Root);
          
           OdbcConnection conn = new OdbcConnection(builder.ConnectionString);
           conn.Open();
           accessDBPSDriveInfo.Connection = conn;

           return accessDBPSDriveInfo;
       } // NewDrive

       /// <summary>
       /// Removes a drive from the provider.
       /// </summary>
       /// <param name="drive">The drive to remove.</param>
       /// <returns>The drive removed.</returns>
       protected override PSDriveInfo RemoveDrive(PSDriveInfo drive)
       {
           // check if drive object is null
           if (drive == null)
           {
               WriteError(new ErrorRecord(
                   new ArgumentNullException("drive"), 
                   "NullDrive",
                   ErrorCategory.InvalidArgument, 
                   drive)
               );

              return null;
           }

           // close ODBC connection to the drive
           AccessDBPSDriveInfo accessDBPSDriveInfo = drive as AccessDBPSDriveInfo;

           if (accessDBPSDriveInfo == null)
           {
               return null;
           }
           accessDBPSDriveInfo.Connection.Close();
         
           return accessDBPSDriveInfo;
       } // RemoveDrive

       #endregion Drive Manipulation

   } // AccessDBProvider

   #endregion AccessDBProvider

   #region AccessDBPSDriveInfo

   /// <summary>
   /// Any state associated with the drive should be held here.
   /// In this case, it's the connection to the database.
   /// </summary>
   internal class AccessDBPSDriveInfo : PSDriveInfo
   {
       private OdbcConnection connection;

       /// <summary>
       /// ODBC connection information.
       /// </summary>
       public OdbcConnection Connection
       {
           get { return connection; }
           set { connection = value; }
       }

       /// <summary>
       /// Constructor that takes one argument
       /// </summary>
       /// <param name="driveInfo">Drive provided by this provider</param>
       public AccessDBPSDriveInfo(PSDriveInfo driveInfo)
           : base(driveInfo)
       { }

   } // class AccessDBPSDriveInfo

   #endregion AccessDBPSDriveInfo
}

See Also

Windows PowerShell Programmer's Guide

Windows PowerShell SDK