重新想象 Windows 8 Store Apps (25) - 选取器: 文件选取窗口, 文件夹选取窗口, 文件保存窗口

2022-12-13 07:38:53

原文:重新想象 Windows 8 Store Apps (25) - 选取器: 文件选取窗口, 文件夹选取窗口, 文件保存窗口

作者：webabcd

介绍
重新想象 Windows 8 Store Apps 之选取器

FileOpenPicker - 选择一个文件或多个文件
FolderPicker - 选择一个文件夹
FileSavePicker - 保存文件到指定路径

示例
1、演示如何通过 FileOpenPicker 选择一个文件或多个文件
Picker/FileOpenPickerDemo.xaml

<Page

    x:Class="XamlDemo.Picker.FileOpenPickerDemo"

    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

    xmlns:local="using:XamlDemo.Picker"

    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"

    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"

    mc:Ignorable="d">

    <Grid Background="Transparent">

        <StackPanel Margin="120 0 0 0">

            <TextBlock Name="lblMsg" FontSize="14.667" />

            <Button Name="btnPickFile" Content="pick a file" Click="btnPickFile_Click_1" Margin="0 10 0 0" />

            <Button Name="btnPickFiles" Content="pick multiple files" Click="btnPickFiles_Click_1" Margin="0 10 0 0" />

        </StackPanel>

    </Grid>

</Page>

Picker/FileOpenPickerDemo.xaml.cs

/*

 * 演示如何通过 FileOpenPicker 选择一个文件或多个文件

 *

 * FileOpenPicker - 文件选择窗口

 *     ViewMode - 文件选择窗口的视图模式，Windows.Storage.Pickers.PickerViewMode 枚举（List 或 Thumbnail）

 *     SuggestedStartLocation - 文件选择窗口所显示的初始路径，Windows.Storage.Pickers.PickerLocationId 枚举

 *         DocumentsLibrary, ComputerFolder, Desktop,, Downloads, HomeGroup, MusicLibrary, PicturesLibrary，VideosLibrary

 *     FileTypeFilter - 允许显示在文件选择窗口的文件类型集合

 *     CommitButtonText - 文件选择窗口的提交按钮的显示文本，此按钮默认显示的文本为“打开”

 *     PickSingleFileAsync() -  弹出文件选择窗口，以让用户选择一个文件

 *     PickMultipleFilesAsync() - 弹出文件选择窗口，以让用户选择多个文件

 */

using System;

using System.Collections.Generic;

using Windows.Storage;

using Windows.Storage.AccessCache;

using Windows.Storage.Pickers;

using Windows.UI.Xaml;

using Windows.UI.Xaml.Controls;

namespace XamlDemo.Picker

{

    public sealed partial class FileOpenPickerDemo : Page

    {

        public FileOpenPickerDemo()

        {

            this.InitializeComponent();

        }

        private async void btnPickFile_Click_1(object sender, RoutedEventArgs e)

        {

            if (XamlDemo.Common.Helper.EnsureUnsnapped())

            {

                // 选择一个文件

                FileOpenPicker openPicker = new FileOpenPicker();

                openPicker.CommitButtonText = "选中此文件";

                openPicker.ViewMode = PickerViewMode.Thumbnail;

                openPicker.SuggestedStartLocation = PickerLocationId.PicturesLibrary;

                openPicker.FileTypeFilter.Add(".jpg");

                openPicker.FileTypeFilter.Add(".gif");

                openPicker.FileTypeFilter.Add(".png");

                // 弹出文件选择窗口

                StorageFile file = await openPicker.PickSingleFileAsync(); // 用户在“文件选择窗口”中完成操作后，会返回对应的 StorageFile 对象

                if (file != null)

                {

                    lblMsg.Text = "选中文件: " + file.Name;

                }

                else

                {

                    lblMsg.Text = "取消了";

                }

            }

        }

        private async  void btnPickFiles_Click_1(object sender, RoutedEventArgs e)

        {

            if (XamlDemo.Common.Helper.EnsureUnsnapped())

            {

                // 选择多个文件

                FileOpenPicker openPicker = new FileOpenPicker();

                openPicker.ViewMode = PickerViewMode.List;

                openPicker.SuggestedStartLocation = PickerLocationId.DocumentsLibrary;

                openPicker.FileTypeFilter.Add("*");

                // 弹出文件选择窗口

                IReadOnlyList<StorageFile> files = await openPicker.PickMultipleFilesAsync(); // 用户在“文件选择窗口”中完成操作后，会返回对应的 StorageFile 对象

                if (files.Count > )

                {

                    lblMsg.Text = "选中文件: ";

                    lblMsg.Text += Environment.NewLine;

                    foreach (StorageFile file in files)

                    {

                        lblMsg.Text += (file.Name);

                        lblMsg.Text += Environment.NewLine;

                    }

                }

                else

                {

                    lblMsg.Text = "取消了";

                }

            }

        }

    }

}

2、演示如何通过 FolderPicker 选择一个文件夹
Picker/FolderPickerDemo.xaml

<Page

    x:Class="XamlDemo.Picker.FolderPickerDemo"

    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

    xmlns:local="using:XamlDemo.Picker"

    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"

    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"

    mc:Ignorable="d">

    <Grid Background="Transparent">

        <StackPanel Margin="120 0 0 0">

            <TextBlock Name="lblMsg" FontSize="14.667" />

            <Button Name="btnPickFolder" Content="pick a folder" Click="btnPickFolder_Click_1" Margin="0 10 0 0 " />

        </StackPanel>

    </Grid>

</Page>

Picker/FolderPickerDemo.xaml.cs

/*

 * 演示如何通过 FolderPicker 选择一个文件夹

 *

 * FolderPicker - 文件夹选择窗口

 *     ViewMode - 文件夹选择窗口的视图模式，Windows.Storage.Pickers.PickerViewMode 枚举（List 或 Thumbnail）

 *     SuggestedStartLocation - 文件夹选择窗口所显示的初始路径，Windows.Storage.Pickers.PickerLocationId 枚举

 *         DocumentsLibrary, ComputerFolder, Desktop,, Downloads, HomeGroup, MusicLibrary, PicturesLibrary，VideosLibrary

 *     FileTypeFilter - 允许显示在文件夹选择窗口的文件类型集合（只能显示符合要求的文件，但是无法选中）

 *     CommitButtonText - 文件夹选择窗口的提交按钮的显示文本，此按钮默认显示的文本为“选择这个文件夹”

 *     PickSingleFolderAsync() - 弹出文件夹选择窗口，以让用户选择一个文件夹

 */

using System;

using Windows.Storage;

using Windows.Storage.Pickers;

using Windows.UI.Xaml;

using Windows.UI.Xaml.Controls;

namespace XamlDemo.Picker

{

    public sealed partial class FolderPickerDemo : Page

    {

        public FolderPickerDemo()

        {

            this.InitializeComponent();

        }

        private async void btnPickFolder_Click_1(object sender, RoutedEventArgs e)

        {

            if (XamlDemo.Common.Helper.EnsureUnsnapped())

            {

                // 选择一个文件夹

                FolderPicker folderPicker = new FolderPicker();

                folderPicker.SuggestedStartLocation = PickerLocationId.Desktop;

                folderPicker.FileTypeFilter.Add(".docx");

                folderPicker.FileTypeFilter.Add(".xlsx");

                folderPicker.FileTypeFilter.Add(".pptx");

                // 弹出文件夹选择窗口

                StorageFolder folder = await folderPicker.PickSingleFolderAsync(); // 用户在“文件夹选择窗口”中完成操作后，会返回对应的 StorageFolder 对象

                if (folder != null)

                {

                    lblMsg.Text = "选中文件夹: " + folder.Name;

                }

                else

                {

                    lblMsg.Text = "取消了";

                }

            }

        }

    }

}

3、演示如何通过 FileSavePicker 保存文件到指定路径
Picker/FileSavePickerDemo.xaml

<Page

    x:Class="XamlDemo.Picker.FileSavePickerDemo"

    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

    xmlns:local="using:XamlDemo.Pikcer"

    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"

    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"

    mc:Ignorable="d">

    <Grid Background="Transparent">

        <StackPanel Margin="120 0 0 0">

            <TextBlock Name="lblMsg" FontSize="14.667" />

            <Button Name="btnSaveFile" Content="save a file" Click="btnSaveFile_Click_1" Margin="0 10 0 0" />

        </StackPanel>

    </Grid>

</Page>

Picker/FileSavePickerDemo.xaml.cs

/*

 * 演示如何通过 FileSavePicker 保存文件到指定路径

 *

 * FileSavePicker - 文件保存窗口

 *     SuggestedStartLocation - 文件保存窗口所显示的初始路径，Windows.Storage.Pickers.PickerLocationId 枚举

 *         DocumentsLibrary, ComputerFolder, Desktop,, Downloads, HomeGroup, MusicLibrary, PicturesLibrary，VideosLibrary

 *     SuggestedFileName - 需要保存的文件的默认文件名

 *     SuggestedSaveFile - 需要保存的文件的默认 StorageFile 对象

 *     FileTypeChoices - 可保存的扩展名集合

 *     DefaultFileExtension - 默认扩展名

 *     CommitButtonText - 文件保存窗口的提交按钮的显示文本，此按钮默认显示的文本为“保存”

 *     PickSaveFileAsync() - 弹出文件保存窗口，以让用户保存文件

 */

using System;

using System.Collections.Generic;

using Windows.Storage;

using Windows.Storage.Pickers;

using Windows.Storage.Provider;

using Windows.UI.Xaml;

using Windows.UI.Xaml.Controls;

namespace XamlDemo.Picker

{

    public sealed partial class FileSavePickerDemo : Page

    {

        public FileSavePickerDemo()

        {

            this.InitializeComponent();

        }

        private async void btnSaveFile_Click_1(object sender, RoutedEventArgs e)

        {

            if (XamlDemo.Common.Helper.EnsureUnsnapped())

            {

                FileSavePicker savePicker = new FileSavePicker();

                savePicker.SuggestedStartLocation = PickerLocationId.DocumentsLibrary;

                // 在扩展名选择框中将会显示：文本(.txt)

                savePicker.FileTypeChoices.Add("文本", new List<string>() { ".txt" });

                savePicker.SuggestedFileName = "webabcdFileSavePicker";

                // 弹出文件保存窗口

                StorageFile file = await savePicker.PickSaveFileAsync(); // 用户在“文件保存窗口”中完成操作后，会返回对应的 StorageFile 对象

                if (file != null)

                {

                    /*

                     * 运行到此，只是在目标地址创建了一个没有任何内容的空白文件而已，接下来开始向文件写入内容

                     */

                    // 告诉 Windows ，从此时开始要防止其它程序更新指定的文件

                    CachedFileManager.DeferUpdates(file);

                    // 将指定的内容保存到指定的文件

                    string textContent = "I am webabcd";

                    await FileIO.WriteTextAsync(file, textContent);

                    // 告诉 Windows ，从此时开始允许其它程序更新指定的文件

                    FileUpdateStatus status = await CachedFileManager.CompleteUpdatesAsync(file);

                    if (status == FileUpdateStatus.Complete)

                    {

                        lblMsg.Text = "文件 " + file.Name + " 保存成功";

                    }

                    lblMsg.Text += Environment.NewLine;

                    lblMsg.Text += "FileUpdateStatus: " + status.ToString();

                }

                else

                {

                    lblMsg.Text = "取消了";

                }

            }

        }

    }

}

OK
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