The following example demonstrates how RadGridView displays a hierarchy based on the data provided by the file system where one folder can have files and folders that can have other files and folders, etc.

In order to achieve the look of the RadGridView from the screenshot above, we need to follow these steps:

1. Create a datasource with an appropriate structure where each data record contains Id that serves as a unique identifier for the record and ParentId that determines the parent of the data record. In our case this is a business object of type FileSystemItem that can serve as a folder and as a document.
   Copy[C#]

   public class FileSystemItem
   {
       int id;
       string name;
       DateTime creationTime;
       int parentFolderId;
       private string type;
   
       public int Id
       {
           get
           {
               return id;
           }
           set
           {
               id = value;
           }
       }
   
       public string FileSystemInfoType
       {
           get
           {
               return type;
           }
           set
           {
               type = value;
           }
       }
   
       public string Name
       {
           get
           {
               return name;
           }
           set
           {
               name = value;
           }
       }
   
       public DateTime CreationTime
       {
           get
           {
               return creationTime;
           }
           set
           {
               creationTime = value;
           }
       }
   
       public int ParentFolderId
       {
           get
           {
               return parentFolderId;
           }
           set
           {
               parentFolderId = value;
           }
       }
   
       public FileSystemItem(int id, string type, string name, DateTime creationTime, int parentFolderId)
       {
           this.id = id;
           this.type = type;
           this.name = name;
           this.creationTime = creationTime;
           this.parentFolderId = parentFolderId;
       }
   }

   Copy[VB.NET]

   Public Class FileSystemItem
       Private id_Renamed As Integer
       Private name_Renamed As String
       Private creationTime_Renamed As Date
       Private parentFolderId_Renamed As Integer
   
       Private type As String
   
       Public Property Id() As Integer
           Get
               Return id_Renamed
           End Get
           Set(ByVal value As Integer)
               id_Renamed = value
           End Set
       End Property
   
       Public Property FileSystemInfoType() As String
           Get
               Return type
           End Get
           Set(ByVal value As String)
               type = value
           End Set
       End Property
   
       Public Property Name() As String
           Get
               Return name_Renamed
           End Get
           Set(ByVal value As String)
               name_Renamed = value
           End Set
       End Property
   
       Public Property CreationTime() As Date
           Get
               Return creationTime_Renamed
           End Get
           Set(ByVal value As Date)
               creationTime_Renamed = value
           End Set
       End Property
   
       Public Property ParentFolderId() As Integer
           Get
               Return parentFolderId_Renamed
           End Get
           Set(ByVal value As Integer)
               parentFolderId_Renamed = value
           End Set
       End Property
   
       Public Sub New(ByVal id As Integer, ByVal type As String, ByVal name As String, ByVal creationTime As Date, ByVal parentFolderId As Integer)
           Me.id_Renamed = id
           Me.type = type
           Me.name_Renamed = name
           Me.creationTime_Renamed = creationTime
           Me.parentFolderId_Renamed = parentFolderId
       End Sub
   End Class

2. Fill a BindingList with objects of type FileSystemItem. The content of the list will depend on the content of the "C:\Program Files (x86)\Telerik" folder:
   Copy[C#]

   BindingList<FileSystemItem> list = new BindingList<FileSystemItem>();
   int fileFolderIndex = 0;
   
   public void GetFilesAndFolders(string dir, int parentId)
   {
       DirectoryInfo di = new DirectoryInfo(dir);
       FileInfo[] rgFiles = di.GetFiles();
       foreach (FileInfo fi in rgFiles)
       {
           fileFolderIndex++;
           list.Add(new FileSystemItem(fileFolderIndex, "File", fi.Name, fi.CreationTime, parentId));
       }
   
       DirectoryInfo[] dirs = di.GetDirectories();
       foreach (DirectoryInfo d in dirs)
       {
           fileFolderIndex++;
           list.Add(new FileSystemItem(fileFolderIndex, "Folder", d.Name, d.CreationTime, parentId));
           GetFilesAndFolders(d.FullName, fileFolderIndex);
       }
   }

   Copy[VB.NET]

   Private list As New BindingList(Of FileSystemItem)()
   Private fileFolderIndex As Integer = 0
   
   Public Sub GetFilesAndFolders(ByVal dir As String, ByVal parentId As Integer)
       Dim di As New DirectoryInfo(dir)
       Dim rgFiles() As FileInfo = di.GetFiles()
       For Each fi As FileInfo In rgFiles
           fileFolderIndex += 1
           list.Add(New FileSystemItem(fileFolderIndex, "File", fi.Name, fi.CreationTime, parentId))
       Next fi
   
       Dim dirs() As DirectoryInfo = di.GetDirectories()
       For Each d As DirectoryInfo In dirs
           fileFolderIndex += 1
           list.Add(New FileSystemItem(fileFolderIndex, "Folder", d.Name, d.CreationTime, parentId))
           GetFilesAndFolders(d.FullName, fileFolderIndex)
       Next d
   End Sub

3. The most imporant step of this example - setting up the Self Referencing mode of RadGridView. To do this, you should call the AddSelfReference method of the Relations collection passing the template that should reflect the structure of the business object and the properties that should determine the parent-child relation:
   Copy[C#]

   this.radGridView1.Relations.AddSelfReference(this.radGridView1.MasterTemplate, "Id", "ParentFolderId");
   this.radGridView1.DataSource = list;

   Copy[VB.NET]

   Me.RadGridView1.Relations.AddSelfReference(Me.RadGridView1.MasterTemplate, "Id", "ParentFolderId")
   Me.RadGridView1.DataSource = list

4. Hide the columns that are not useful to your clients. These columns in our case are Id, ParentFolderId and FileSystemInfoType:
   Copy[C#]

   this.radGridView1.Columns["Id"].IsVisible = false;
   this.radGridView1.Columns["ParentFolderId"].IsVisible = false;
   this.radGridView1.Columns["FileSystemInfoType"].IsVisible = false;

   Copy[VB.NET]

   Me.RadGridView1.Columns("Id").IsVisible = False
   Me.RadGridView1.Columns("ParentFolderId").IsVisible = False
   Me.RadGridView1.Columns("FileSystemInfoType").IsVisible = False

5. Last, but not least, you may want to show different images depending on the actual file system types of the data records. To do this, you should handle the CellFormatting event, check if the FileSystemInfoType is File or Folder and set the appropriate image accordingly:
   Copy[C#]

   // Getting the images from the resources of the project
   Image documentImage = SamplesCS.Properties.Resources.Document;
   Image folderImage = SamplesCS.Properties.Resources.Folder;
   
   void radGridView1_CellFormatting(object sender, Telerik.WinControls.UI.CellFormattingEventArgs e)
   {
       GridDataCellElement dataCell = e.CellElement as GridDataCellElement;
   
       if (dataCell.ColumnInfo.Name == "Name")
       {
           GridViewDataRowInfo dataRow = dataCell.RowInfo as GridViewDataRowInfo;
           if (dataRow != null)
           {
               dataCell.ImageAlignment = ContentAlignment.MiddleLeft;
   
               string valueType = Convert.ToString(dataRow.Cells["FileSystemInfoType"].Value).ToUpperInvariant();
   
               if (valueType.Contains("FILE"))
               {
                   dataCell.Image = documentImage;
               }
               else
               {
                   dataCell.Image = folderImage;
               }
   
               dataCell.TextImageRelation = TextImageRelation.ImageBeforeText;
           }
       }
       else
       {
           dataCell.ResetValue(LightVisualElement.ImageProperty, Telerik.WinControls.ValueResetFlags.Local);
           dataCell.ResetValue(LightVisualElement.ImageAlignmentProperty, Telerik.WinControls.ValueResetFlags.Local);
           dataCell.ResetValue(LightVisualElement.TextImageRelationProperty, Telerik.WinControls.ValueResetFlags.Local);
           dataCell.ResetValue(LightVisualElement.ImageLayoutProperty, Telerik.WinControls.ValueResetFlags.Local);
       }
   }

   Copy[VB.NET]

   ' Getting the images from the resources of the project
   Private documentImage As Image = SamplesVB.My.Resources.Document
   Private folderImage As Image = SamplesVB.My.Resources.Folder
   
   Private Sub radGridView1_CellFormatting(ByVal sender As Object, ByVal e As Telerik.WinControls.UI.CellFormattingEventArgs)
       Dim dataCell As GridDataCellElement = TryCast(e.CellElement, GridDataCellElement)
   
       If dataCell.ColumnInfo.Name = "Name" Then
           Dim dataRow As GridViewDataRowInfo = TryCast(dataCell.RowInfo, GridViewDataRowInfo)
           If dataRow IsNot Nothing Then
               dataCell.ImageAlignment = ContentAlignment.MiddleLeft
   
               Dim valueType As String = Convert.ToString(dataRow.Cells("FileSystemInfoType").Value).ToUpperInvariant()
   
               If valueType.Contains("FILE") Then
                   dataCell.Image = documentImage
               Else
                   dataCell.Image = folderImage
               End If
   
               dataCell.TextImageRelation = TextImageRelation.ImageBeforeText
           End If
       Else
           dataCell.ResetValue(LightVisualElement.ImageProperty, Telerik.WinControls.ValueResetFlags.Local)
           dataCell.ResetValue(LightVisualElement.ImageAlignmentProperty, Telerik.WinControls.ValueResetFlags.Local)
           dataCell.ResetValue(LightVisualElement.TextImageRelationProperty, Telerik.WinControls.ValueResetFlags.Local)
           dataCell.ResetValue(LightVisualElement.ImageLayoutProperty, Telerik.WinControls.ValueResetFlags.Local)
       End If
   End Sub