IFileData.LoadFromStream(String, Stream) Method

Loads the file data from a stream.

Namespace: DevExpress.Persistent.Base

Assembly: DevExpress.Persistent.Base.v24.2.dll

NuGet Package: DevExpress.Persistent.Base

Declaration

C#

void LoadFromStream(
    string fileName,
    Stream stream
)

VB.NET

Sub LoadFromStream(
    fileName As String,
    stream As Stream
)

Parameters

Name	Type	Description
fileName	String	A string that is the file name.
stream	Stream	A Stream that is the file content.

Remarks

The example below demonstrates how to use the LoadFromStream method to upload a Contact’s file into a portfolio.

C#

using System.IO;
using DevExpress.ExpressApp;
using DevExpress.ExpressApp.Actions;
using DevExpress.Persistent.Base;
using DevExpress.Persistent.BaseImpl;
using MainDemo.Module.BusinessObjects;
// ...
public class UpdatePortfolioController : ObjectViewController<DetailView, Resume> {
    public UpdatePortfolioController() {
        SimpleAction updatePortfolioAction = new SimpleAction(this, "UpdatePortfolio", PredefinedCategory.Edit);
        updatePortfolioAction.SelectionDependencyType = SelectionDependencyType.RequireSingleObject;
        updatePortfolioAction.Execute += updatePortfolioAction_Execute;
    }
    private void updatePortfolioAction_Execute(object sender, SimpleActionExecuteEventArgs e) {
        FileData currentFile = ViewCurrentObject.File;
        if(currentFile != null && !currentFile.IsEmpty) {
            FileData fileCopy = ObjectSpace.CreateObject<FileData>();
            using(var stream = new MemoryStream()) {
                currentFile.SaveToStream(stream);
                stream.Position = 0;
                fileCopy.LoadFromStream(currentFile.FileName, stream);
            }
            PortfolioFileData portfolio = ObjectSpace.CreateObject<PortfolioFileData>();
            portfolio.File = fileCopy;
            ViewCurrentObject.Portfolio.Add(portfolio);
            ObjectSpace.CommitChanges();
        }
    }
}

VB.NET

Imports System.IO
Imports DevExpress.ExpressApp
Imports DevExpress.ExpressApp.Actions
Imports DevExpress.Persistent.Base
Imports DevExpress.Persistent.BaseImpl
Imports MainDemo.Module.BusinessObjects

Public Class UpdatePortfolioController
    Inherits ObjectViewController(Of DetailView, [Resume])

    Public Sub New()
        Dim updatePortfolioAction As New SimpleAction(Me, "UpdatePortfolio", PredefinedCategory.Edit)
        updatePortfolioAction.SelectionDependencyType = SelectionDependencyType.RequireSingleObject
        AddHandler updatePortfolioAction.Execute, AddressOf updatePortfolioAction_Execute
    End Sub
    Private Sub updatePortfolioAction_Execute(ByVal sender As Object, ByVal e As SimpleActionExecuteEventArgs)
        Dim currentFile As FileData = ViewCurrentObject.File
        If currentFile IsNot Nothing AndAlso Not currentFile.IsEmpty Then
            Dim fileCopy As FileData = ObjectSpace.CreateObject(Of FileData)()
            Using stream As MemoryStream = New MemoryStream()
                currentFile.SaveToStream(stream)
                stream.Position = 0
                fileCopy.LoadFromStream(currentFile.FileName, stream)
            End Using
            Dim portfolio As PortfolioFileData = ObjectSpace.CreateObject(Of PortfolioFileData)()
            portfolio.File = fileCopy
            ViewCurrentObject.Portfolio.Add(portfolio)
            ObjectSpace.CommitChanges()
        End If
    End Sub
End Class

Here, FileData is a built-in class that implements the IFileData interface.