IWebSpreadsheetValueStorage Interface

Declares members of he Spreadsheet editor’s value storage.

Namespace: DevExpress.ExpressApp.Office.Web

Assembly: DevExpress.ExpressApp.Office.Web.v19.2.dll

Declaration

C#

public interface IWebSpreadsheetValueStorage

VB.NET

Public Interface IWebSpreadsheetValueStorage

Remarks

A Spreadsheet editor’s value storage allows you to implement custom logic executed when saving or loading a RichText document. Follow the steps below to create a custom value storage that specifies a file storage format.

Tip

We recommend you to use the ASPxSpreadsheetPropertyEditor.DocumentFormat property to specify a document storage format (see How to: Customize the Spreadsheet Editor). The example below is shown for demonstration purposes.

1. In the ASP.NET Module project, create a class that implements the IWebSpreadsheetValueStorage interface as shown below:

   C#

   using DevExpress.ExpressApp.Office.Web;
   using DevExpress.Spreadsheet;
   using DevExpress.Web.ASPxSpreadsheet;
   using System.IO;
   // ...
   public class WebOpenXmlSpreadsheetValueStorage : IWebSpreadsheetValueStorage {
       public object GetValue(ASPxSpreadsheet control) {
           using (MemoryStream memoryStream = new MemoryStream()) {
               control.SaveCopy(memoryStream, DocumentFormat.OpenXml);
               using (StreamReader streamReader = new StreamReader(memoryStream)) {
                   memoryStream.Seek(0, SeekOrigin.Begin);
                   return streamReader.ReadToEnd();
               }
           }
       }
       public void SetValue(ASPxSpreadsheet control, object propertyValue, string documentID) {
           control.Open(documentID, DocumentFormat.OpenXml, () => (byte[])propertyValue);
       }
   }
   

   VB.NET

   Imports DevExpress.ExpressApp.Office.Web
   Imports DevExpress.Spreadsheet
   Imports DevExpress.Web.ASPxSpreadsheet
   Imports System.IO
   ' ...
   Public Class WebOpenXmlSpreadsheetValueStorage
       Implements IWebSpreadsheetValueStorage
       Public Function GetValue(ByVal control As ASPxSpreadsheet) As Object _
           Implements IWebSpreadsheetValueStorage.GetValue
           Using memoryStream As New MemoryStream()
               control.SaveCopy(memoryStream, DocumentFormat.OpenXml)
               Using streamReader As New StreamReader(memoryStream)
                   memoryStream.Seek(0, SeekOrigin.Begin)
                   Return streamReader.ReadToEnd()
               End Using
           End Using
       End Function
       Public Sub SetValue(ByVal control As ASPxSpreadsheet, ByVal propertyValue As Object, ByVal documentID As String) _
           Implements IWebSpreadsheetValueStorage.SetValue
           control.Open(documentID, DocumentFormat.OpenXml, Function() DirectCast(propertyValue, Byte()))
       End Sub
   End Class
   

2. Create a View Controller and access the ASPxSpreadsheetPropertyEditor as described in the Ways to Access UI Elements and Their Controls topic. Set the editor’s ValueStorage property to an instance of CustomWebSpreadsheetValueStorage as shown below.

   C#

   using DevExpress.ExpressApp;
   using DevExpress.ExpressApp.Office.Web;
   // ...
   public class WebSpreadsheetStorageController : ObjectViewController<DetailView, Document> {
       protected override void OnActivated() {
           base.OnActivated();
           ASPxSpreadsheetPropertyEditor spreadsheetPropertyEditor = View.FindItem("Data") as ASPxSpreadsheetPropertyEditor;
           if (spreadsheetPropertyEditor != null) {
               spreadsheetPropertyEditor.ValueStorage = new WebOpenXmlSpreadsheetValueStorage();
           }
       }
   }
   

   VB.NET

   Imports DevExpress.ExpressApp
   Imports DevExpress.ExpressApp.Office.Web
   ' ...
   Public Class WebSpreadsheetStorageController
       Inherits ObjectViewController(Of DetailView, Document)
       Protected Overrides Sub OnActivated()
           MyBase.OnActivated()
           Dim spreadsheetPropertyEditor As ASPxSpreadsheetPropertyEditor = TryCast(View.FindItem("Data"), ASPxSpreadsheetPropertyEditor)
           If spreadsheetPropertyEditor IsNot Nothing Then
               spreadsheetPropertyEditor.ValueStorage = New WebOpenXmlSpreadsheetValueStorage()
           End If
       End Sub
   End Class