SaveFileDialogService

• Jul 11, 2021
• 5 minutes to read

The SaveFileDialogService is an ISaveFileDialogService implementation that allows you to save data of a ViewModel to a file by using the standard dialog box.

To use the SaveFileDialogService, attach it to a View as described in Quick Actions.

XAML

<UserControl x:Class="FileDialogServicesSample.Views.FileDialogsView"
    ...
    xmlns:dxmvvm="http://schemas.devexpress.com/winfx/2008/xaml/mvvm">
    <dxmvvm:Interaction.Behaviors>
        <dxmvvm:SaveFileDialogService />
    </dxmvvm:Interaction.Behaviors>
</UserControl>

Next, access the attached service and use the service’s ISaveFileDialogService.ShowDialog method to display a dialog box.

C#

[POCOViewModel]
public class FileDialogsViewModel {

    protected ISaveFileDialogService SaveFileDialogService { get { return this.GetService<ISaveFileDialogService>(); } }
    ...
    public void Save() {
        ...
        if (SaveFileDialogService.ShowDialog()) {
            ...
        }
    }
}

VB.NET

<POCOViewModel> _
Public Class FileDialogsViewModel
    Protected ReadOnly Property SaveFileDialogService() As ISaveFileDialogService
        Get
            Return Me.GetService(Of ISaveFileDialogService)()
        End Get
    End Property
    ...
    Public Sub Save()
        ...
        If SaveFileDialogService.ShowDialog() Then
            ...
        End If
    End Sub
End Class

A description on how to obtain a service from a View Model is available here: Services in POCO objects and Services in ViewModelBase descendants.

Then, use the FileInfoWrapper object that is stored in the ISaveFileDialogService.File property to save your data. By default, the SaveFileDialogService uses values of DefaultFileName and SaveFileDialogService.DefaultExt properties to name the file that will be used as the ViewModel’s data storage. However, an end-user can specify the file name manually by using the corresponding dialog box fields.

Note

The SaveFileDialogService uses its own FileInfoWrapper class implementing the IFileInfo interface to represent the selected file(s). This class provides the capabilities of the standard FileInfo to work with FileStream objects.

Example

View Example

FileDialogsViewModel.vb

Imports DevExpress.Mvvm
Imports DevExpress.Mvvm.DataAnnotations
Imports DevExpress.Mvvm.POCO
Imports System.IO
Imports System.Linq

Namespace FileDialogServicesSample.ViewModels
    <POCOViewModel> _
    Public Class FileDialogsViewModel
        #Region "Common properties"
        Public Overridable Property Filter() As String
        Public Overridable Property FilterIndex() As Integer
        Public Overridable Property Title() As String
        Private privateDialogResult As Boolean
        Public Overridable Property DialogResult() As Boolean
            Get
                Return privateDialogResult
            End Get
            Protected Set(ByVal value As Boolean)
                privateDialogResult = value
            End Set
        End Property
        Private privateResultFileName As String
        Public Overridable Property ResultFileName() As String
            Get
                Return privateResultFileName
            End Get
            Protected Set(ByVal value As String)
                privateResultFileName = value
            End Set
        End Property
        Public Overridable Property FileBody() As String
        #End Region

        #Region "SaveFileDialogService specific properties"
        Public Overridable Property DefaultExt() As String
        Public Overridable Property DefaultFileName() As String
        Public Overridable Property OverwritePrompt() As Boolean
        #End Region

        Protected ReadOnly Property SaveFileDialogService() As ISaveFileDialogService
            Get
                Return Me.GetService(Of ISaveFileDialogService)()
            End Get
        End Property
        Protected ReadOnly Property OpenFileDialogService() As IOpenFileDialogService
            Get
                Return Me.GetService(Of IOpenFileDialogService)()
            End Get
        End Property

        Public Sub New()
            Filter = "Text Files (.txt)|*.txt|All Files (*.*)|*.*"
            FilterIndex = 1
            Title = "Custom Dialog Title"
            DefaultExt = "txt"
            DefaultFileName = "Document1"
            OverwritePrompt = True
        End Sub

        Public Sub Open()
            OpenFileDialogService.Filter = Filter
            OpenFileDialogService.FilterIndex = FilterIndex
            DialogResult = OpenFileDialogService.ShowDialog()
            If Not DialogResult Then
                ResultFileName = String.Empty
            Else
                Dim file As IFileInfo = OpenFileDialogService.Files.First()
                ResultFileName = file.Name
                Using stream = file.OpenText()
                    FileBody = stream.ReadToEnd()
                End Using
            End If
        End Sub

        Public Sub Save()
            SaveFileDialogService.DefaultExt = DefaultExt
            SaveFileDialogService.DefaultFileName = DefaultFileName
            SaveFileDialogService.Filter = Filter
            SaveFileDialogService.FilterIndex = FilterIndex
            DialogResult = SaveFileDialogService.ShowDialog()
            If Not DialogResult Then
                ResultFileName = String.Empty
            Else
                Using stream = New StreamWriter(SaveFileDialogService.OpenFile())
                    stream.Write(FileBody)
                End Using
            End If
        End Sub

    End Class
End Namespace

FileDialogsView.xaml

<UserControl 
    x:Class="FileDialogServicesSample.Views.FileDialogsView"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:dx="http://schemas.devexpress.com/winfx/2008/xaml/core"           
    xmlns:dxb="http://schemas.devexpress.com/winfx/2008/xaml/bars" 
    xmlns:dxe="http://schemas.devexpress.com/winfx/2008/xaml/editors"  
    xmlns:dxr="http://schemas.devexpress.com/winfx/2008/xaml/ribbon"
    xmlns:dxmvvm="http://schemas.devexpress.com/winfx/2008/xaml/mvvm" 
    xmlns:ViewModels="clr-namespace:FileDialogServicesSample.ViewModels"
    mc:Ignorable="d" d:DesignHeight="300" d:DesignWidth="300"
    DataContext="{dxmvvm:ViewModelSource Type={x:Type ViewModels:FileDialogsViewModel}}">
    <dxmvvm:Interaction.Behaviors>
        <dxmvvm:OpenFileDialogService Title="{Binding Title}"/>
        <dxmvvm:SaveFileDialogService Title="{Binding Title}"/>
    </dxmvvm:Interaction.Behaviors>
    <DockPanel>
        <dxr:RibbonControl 
            DockPanel.Dock="Top" 
            ShowApplicationButton="False" 
            ToolbarShowMode="Hide" 
            RibbonTitleBarVisibility="Collapsed">
            <dxr:RibbonDefaultPageCategory Caption="Default Category">
                <dxr:RibbonPage Caption="File">
                    <dxr:RibbonPageGroup Caption="Actions">
                        <dxb:BarButtonItem 
                            Content="Open"
                            Command="{Binding OpenCommand}" 
                            Glyph="{dx:DXImage Image=Open_16x16.png}" 
                            LargeGlyph="{dx:DXImage Image=Open2_32x32.png}" 
                            RibbonStyle="Large"/>
                        <dxb:BarButtonItem 
                            Content="Save" 
                            Command="{Binding SaveCommand}" 
                            Glyph="{dx:DXImage Image=Save_16x16.png}" 
                            LargeGlyph="{dx:DXImage Image=Save_32x32.png}" 
                            RibbonStyle="Large"/>
                    </dxr:RibbonPageGroup>
                    <dxr:RibbonPageGroup Caption="Settings">
                        <dxb:BarEditItem Content="Title" EditValue="{Binding Title}">
                            <dxb:BarEditItem.EditSettings>
                                <dxe:TextEditSettings/>
                            </dxb:BarEditItem.EditSettings>
                        </dxb:BarEditItem>
                        <dxb:BarEditItem Content="Filter" EditValue="{Binding Filter}">
                            <dxb:BarEditItem.EditSettings>
                                <dxe:TextEditSettings/>
                            </dxb:BarEditItem.EditSettings>
                        </dxb:BarEditItem>
                        <dxb:BarEditItem Content="Filter Index" EditValue="{Binding FilterIndex}">
                            <dxb:BarEditItem.EditSettings>
                                <dxe:TextEditSettings/>
                            </dxb:BarEditItem.EditSettings>
                        </dxb:BarEditItem>
                    </dxr:RibbonPageGroup>
                </dxr:RibbonPage>
            </dxr:RibbonDefaultPageCategory>
        </dxr:RibbonControl>
        <dxr:RibbonStatusBarControl DockPanel.Dock="Bottom">
            <dxr:RibbonStatusBarControl.RightItems>
                <dxb:BarStaticItem Content="{Binding DialogResult}">
                    <dxb:BarStaticItem.ContentTemplate>
                        <DataTemplate>
                            <StackPanel Orientation="Horizontal">
                                <TextBlock Text="Dialog Result: "/>
                                <TextBlock Text="{Binding}"/>
                            </StackPanel>
                        </DataTemplate>
                    </dxb:BarStaticItem.ContentTemplate>
                </dxb:BarStaticItem>
            </dxr:RibbonStatusBarControl.RightItems>
        </dxr:RibbonStatusBarControl>
        <TextBox 
            Text="{Binding FileBody, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" 
            AcceptsReturn="True" 
            TextWrapping="Wrap"/>
    </DockPanel>
</UserControl>

FileDialogsViewModel.cs

using DevExpress.Mvvm;
using DevExpress.Mvvm.DataAnnotations;
using DevExpress.Mvvm.POCO;
using System.IO;
using System.Linq;

namespace FileDialogServicesSample.ViewModels
{
    [POCOViewModel]
    public class FileDialogsViewModel {
        #region Common properties
        public virtual string Filter { get; set; }
        public virtual int FilterIndex { get; set; }
        public virtual string Title { get; set; }
        public virtual bool DialogResult { get; protected set; }
        public virtual string ResultFileName { get; protected set; }
        public virtual string FileBody { get; set; }
        #endregion

        #region SaveFileDialogService specific properties
        public virtual string DefaultExt { get; set; }
        public virtual string DefaultFileName { get; set; }
        public virtual bool OverwritePrompt { get; set; }
        #endregion

        protected ISaveFileDialogService SaveFileDialogService { get { return this.GetService<ISaveFileDialogService>(); } }
        protected IOpenFileDialogService OpenFileDialogService { get { return this.GetService<IOpenFileDialogService>(); } }

        public FileDialogsViewModel() {
            Filter = "Text Files (.txt)|*.txt|All Files (*.*)|*.*";
            FilterIndex = 1;
            Title = "Custom Dialog Title";
            DefaultExt = "txt";
            DefaultFileName = "Document1";
            OverwritePrompt = true;
        }

        public void Open() {
            OpenFileDialogService.Filter = Filter;
            OpenFileDialogService.FilterIndex = FilterIndex;
            DialogResult = OpenFileDialogService.ShowDialog();
            if (!DialogResult) {
                ResultFileName = string.Empty;
            } else {
                IFileInfo file = OpenFileDialogService.Files.First();
                ResultFileName = file.Name;
                using (var stream = file.OpenText()) {
                    FileBody = stream.ReadToEnd();
                }
            }
        }

        public void Save() {
            SaveFileDialogService.DefaultExt = DefaultExt;
            SaveFileDialogService.DefaultFileName = DefaultFileName;
            SaveFileDialogService.Filter = Filter;
            SaveFileDialogService.FilterIndex = FilterIndex;
            DialogResult = SaveFileDialogService.ShowDialog();
            if (!DialogResult) {
                ResultFileName = string.Empty;
            } else {
                using (var stream = new StreamWriter(SaveFileDialogService.OpenFile())) {
                    stream.Write(FileBody);
                }
            }
        }

    }
}