免费开源Blazor在线Ico转换工具
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1. 功能效果演示
仓库地址：IcoTool[1]
在线演示地址：https://tool.dotnet9.com/ico[2]
演示下文件上传、转换结果：
通过该工具及代码，能了解到：
使用Blazor怎么上传文件到服务器(Blazor Server)。
怎么从服务器下载文件。
如何将png等图片转换为Ico图片。
下面对该工具的实现代码做个简单说明，不太清楚的可以留言交流。
2. 实现说明
通过该工具，能了解到：
使用Blazor怎么上传文件到服务器(Blazor Server)。
怎么从服务器下载文件。
如何将png等图片转换为Ico图片。
下面对该工具的实现代码做个简单说明，不太清楚的可以留言交流。
2.1 其他图片上传
使用的MASA Blazor[3]上传组件MFileInput[4]，看下面的代码，就一个上传组件加上传时文件保存操作，代码文件：IcoTool.razor[5]
<MFileInput TValue="IBrowserFile"
Placeholder="@T("IcoToolMFileInputPlaceholder")"
Rules="_rules"
ShowSize
OnChange="@LoadFile"
Accept="image/png, image/jpeg, image/jpg, image/bmp"
Label="@T("IcoToolMFileInputLabel")">
</MFileInput>
@code
private bool _loading;
private string _sourceFilePath = "";
[Inject] public I18n I18N get; set; = default!;
[Inject] public IJSRuntime Js get; set; = default!;
protected override async Task OnInitializedAsync()
_rules.Add(value => (value==null|| value.Size < 2 * 1024 * 1024 )? true : T("IcoToolFileSizeLimitMessage"));
await base.OnInitializedAsync();
private async Task LoadFile(IBrowserFile? e)
if (e == null)
_destFilePath = _sourceFilePath = string.Empty;
return;
_destFilePath = string.Empty;
if (!string.IsNullOrWhiteSpace(_sourceFilePath) && File.Exists(_sourceFilePath)) File.Delete(_sourceFilePath);
var saveImageDir = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "wwwroot", ImageDirName);
if (!Directory.Exists(saveImageDir)) Directory.CreateDirectory(saveImageDir);
_sourceFilePath = Path.Combine(saveImageDir, DateTime.UtcNow.ToString("yyyyMMddHHmmssfff"));
await using var fs = new FileStream(_sourceFilePath, FileMode.Create);
await e.OpenReadStream().CopyToAsync(fs);
2.2 核心代码：其他图片转Ico
参考代码：https://gist.github.com/darkfall/1656050[6]
因为使用到Bitmap，vs会提示只支持Windows平台，目前工具程序也部署在Windows Server 2019服务器上，如果有其他转换代码，支持跨平台欢迎技术讨论，下面给出我使用的其他图片转Ico的代码，代码路径在：ImagingHelper.cs[7]
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
namespace Dotnet9.Tools.Images;
/// <summary>
/// Adapted from this gist: https://gist.github.com/darkfall/1656050
/// Provides helper methods for imaging
/// </summary>
public static class ImagingHelper
public const string FileheadBmp = "6677";
public const string FileheadJpg = "255216";
public const string FileheadPng = "13780";
public const string FileheadGif = "7173";
private static readonly Dictionary<ImageType, string> ImageTypeHead = new()
ImageType.Bmp, FileheadBmp ,
ImageType.Jpg, FileheadJpg ,
ImageType.Png, FileheadPng ,
ImageType.Gif, FileheadGif
;
public static bool IsPicture(string filePath, out string fileHead)
fileHead = string.Empty;
try
var fs = new FileStream(filePath, FileMode.Open, FileAccess.Read);
var reader = new BinaryReader(fs);
var fileClass = $"reader.ReadByte().ToString()reader.ReadByte().ToString()";
reader.Close();
fs.Close();
if (fileClass is not (FileheadBmp or FileheadJpg or FileheadPng or FileheadGif))
return false;
fileHead = fileClass;
return true;
catch
return false;
public static bool IsPictureType(string filePath, ImageType imageType)
var isPicture = IsPicture(filePath, out var fileHead);
if (!isPicture) return false;
return ImageTypeHead[imageType] == fileHead;
/// <summary>
/// Converts a PNG image to a icon (ico) with all the sizes windows likes
/// </summary>
/// <param name="inputBitmap">The input bitmap</param>
/// <param name="output">The output stream</param>
/// <returns>Wether or not the icon was succesfully generated</returns>
public static bool ConvertToIcon(Bitmap inputBitmap, Stream output)
var sizes = new[] 256, 48, 32, 16 ;
// Generate bitmaps for all the sizes and toss them in streams
var imageStreams = new List<MemoryStream>();
foreach (var size in sizes)
var newBitmap = ResizeImage(inputBitmap, size, size);
var memoryStream = new MemoryStream();
newBitmap.Save(memoryStream, ImageFormat.Png);
imageStreams.Add(memoryStream);
var iconWriter = new BinaryWriter(output);
var offset = 0;
// 0-1 reserved, 0
iconWriter.Write((byte)0);
iconWriter.Write((byte)0);
// 2-3 image type, 1 = icon, 2 = cursor
iconWriter.Write((short)1);
// 4-5 number of images
iconWriter.Write((short)sizes.Length);
offset += 6 + 16 * sizes.Length;
for (var i = 0; i < sizes.Length; i++)
// image entry 1
// 0 image width
iconWriter.Write((byte)sizes[i]);
// 1 image height
iconWriter.Write((byte)sizes[i]);
// 2 number of colors
iconWriter.Write((byte)0);
// 3 reserved
iconWriter.Write((byte)0);
// 4-5 color planes
iconWriter.Write((short)0);
// 6-7 bits per pixel
iconWriter.Write((short)32);
// 8-11 size of image data
iconWriter.Write((int)imageStreams[i].Length);
// 12-15 offset of image data
iconWriter.Write(offset);
offset += (int)imageStreams[i].Length;
for (var i = 0; i < sizes.Length; i++)
// write image data
// png data must contain the whole png data file
iconWriter.Write(imageStreams[i].ToArray());
imageStreams[i].Close();
iconWriter.Flush();
return true;
/// <summary>
/// Converts a PNG image to a icon (ico)
/// </summary>
/// <param name="input">The input stream</param>
/// <param name="output">The output stream</param
/// <returns>Wether or not the icon was succesfully generated</returns>
public static bool ConvertToIcon(Stream input, Stream output)
var inputBitmap = (Bitmap)Image.FromStream(input);
return ConvertToIcon(inputBitmap, output);
/// <summary>
/// Converts a PNG image to a icon (ico)
/// </summary>
/// <param name="inputPath">The input path</param>
/// <param name="outputPath">The output path</param>
/// <returns>Wether or not the icon was succesfully generated</returns>
public static bool ConvertToIcon(string inputPath, string outputPath)
using var inputStream = new FileStream(inputPath, FileMode.Open);
using var outputStream = new FileStream(outputPath, FileMode.OpenOrCreate);
return ConvertToIcon(inputStream, outputStream);
/// <summary>
/// Converts an image to a icon (ico)
/// </summary>
/// <param name="inputImage">The input image</param>
/// <param name="outputPath">The output path</param>
/// <returns>Wether or not the icon was succesfully generated</returns>
public static bool ConvertToIcon(Image inputImage, string outputPath)
using var outputStream = new FileStream(outputPath, FileMode.OpenOrCreate);
return ConvertToIcon(new Bitmap(inputImage), outputStream);
/// <summary>
/// Resize the image to the specified width and height.
/// Found on stackoverflow: https://stackoverflow.com/questions/1922040/resize-an-image-c-sharp
/// </summary>
/// <param name="image">The image to resize.</param>
/// <param name="width">The width to resize to.</param>
/// <param name="height">The height to resize to.</param>
/// <returns>The resized image.</returns>
public static Bitmap ResizeImage(Image image, int width, int height)
var destRect = new Rectangle(0, 0, width, height);
var destImage = new Bitmap(width, height);
destImage.SetResolution(image.HorizontalResolution, image.VerticalResolution);
using var graphics = Graphics.FromImage(destImage);
graphics.CompositingMode = CompositingMode.SourceCopy;
graphics.CompositingQuality = CompositingQuality.HighQuality;
graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
graphics.SmoothingMode = SmoothingMode.HighQuality;
graphics.PixelOffsetMode = PixelOffsetMode.HighQuality;
using var wrapMode = new ImageAttributes();
wrapMode.SetWrapMode(WrapMode.TileFlipXY);
graphics.DrawImage(image, destRect, 0, 0, image.Width, image.Height, GraphicsUnit.Pixel, wrapMode);
return destImage;
public enum ImageType
Bmp,
Jpg,
Png,
Gif
简单的单元测试还是要有的，代码见：ImageHelperTests.cs[8]
using Dotnet9.Tools.Images;
namespace Dotnet9.Tools.Tests.Images;
public class ImageHelperTests
[Fact]
public void IsPicture()
var testFilePath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "TestFiles", "logo.png");
Assert.True(File.Exists(testFilePath));
var isPicture = ImagingHelper.IsPicture(testFilePath, out var typename);
Assert.True(isPicture);
[Fact]
public void IsNotPicture()
var testFilePath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "TestFiles", "test.txt");
Assert.True(File.Exists(testFilePath));
var isPicture = ImagingHelper.IsPicture(testFilePath, out var typename);
Assert.False(isPicture);
[Fact]
public void IsPngFile()
var testFilePath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "TestFiles", "logo.png");
Assert.True(File.Exists(testFilePath));
var isPng = ImagingHelper.IsPictureType(testFilePath, ImageType.Png);
Assert.True(isPng);
[Fact]
public void ShouldConvertPngToIcon()
var sourcePng = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "TestFiles", "logo.png");
var destIco = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "TestFiles", "logo.ico");
Assert.True(File.Exists(sourcePng));
Assert.False(File.Exists(destIco));
ImagingHelper.ConvertToIcon(sourcePng, destIco);
Assert.True(File.Exists(destIco));
File.Delete(destIco);
页面调用Ico转换功能代码如下，提供一个触发转换的按钮和执行转换的方法，代码文件：IcoTool.razor[9]
@if (!string.IsNullOrWhiteSpace(_sourceFilePath) && File.Exists(_sourceFilePath))
<MButton class="ma-2 white--text"
Loading="_loading"
Disabled="_loading"
Depressed Color="primary"
OnClick="@ConvertToIcon">
<LoaderContent>
<span>@T("IcoToolMButtonLoaderContent")</span>
</LoaderContent>
<ChildContent>
<span>@T("IcoToolMButtonChildContent")</span>
</ChildContent>
</MButton>
@code
private async Task ConvertToIcon()
if (!string.IsNullOrWhiteSpace(_destFilePath) && File.Exists(_destFilePath))
await DownloadIco();
return;
_loading = true;
if (!string.IsNullOrWhiteSpace(_sourceFilePath) && File.Exists(_sourceFilePath))
_destFilePath = $"_sourceFilePath.ico";
if (ImagingHelper.ConvertToIcon(_sourceFilePath, _destFilePath)) await DownloadIco();
_loading = false;
2.3 转换后的Ico文件下载
文件转换成功后，怎么提供下载呢？
起初想使用一个<a href="/files/xxx.ico" target="_blank">xxx.ico</a>标签提供浏览下载的，但动态生成的图片无法访问，不知道什么原因，只能暂时采用一个折衷的方式，有朋友有好的想法欢迎留言。
目前采用的是提供按钮下载，下面是封装的js下载方法，来自微软的文档：ASP.NET Core Blazor file downloads[10]
我把JS代码放_Layout.cshtml[11]：
<script>
// 省略部分代码
async function downloadFileFromStream(fileName, contentStreamReference)
const arrayBuffer = await contentStreamReference.arrayBuffer();
const blob = new Blob([arrayBuffer]);
const url = URL.createObjectURL(blob);
triggerFileDownload(fileName, url);
URL.revokeObjectURL(url);
function triggerFileDownload(fileName, url)
const anchorElement = document.createElement('a');
anchorElement.href = url;
if (fileName)
anchorElement.download = fileName;
anchorElement.click();
anchorElement.remove();
</script>页面下载时使用以下代码，使用到JS互操作(什么是JS互操作？可以参考我转载的这篇文章了解首页.NETBlazorBlazor Server (14/30)大家一起学Blazor：javascript interop(互操作))，代码放：IcoTool.razor[12]
@inject IJSRuntime JS
// 省略n多代码
@code
private async Task DownloadIco()
await using var fileStream = new FileStream(_destFilePath, FileMode.Open);
using var streamRef = new DotNetStreamReference(fileStream);
await Js.InvokeVoidAsync("downloadFileFromStream", Path.GetFileName(_destFilePath), streamRef);
3. 总结
Blazor组件库使用的MASA Blazor[13]，很美观大方的
Material Design设计风格。Ico转换，使用到了
System.Drawing.Common包的Bitmap，.NET 6开始不支持跨平台，提示只支持Windows平台。本工具使用7.0.100-preview.1[14]开发、编译、上线，使用.NET 6[15]的同学，请放心使用，可以无缝升级。
Dotnet9工具箱会不断添加新的免费、开源、在线工具，欢迎star支持，有什么需求我会考虑加上，仓库地址：Dotnet9.Tools[16]，可提交issue[17]、网站留言[18]、微信公众号(dotnet9)联系等等。
本工具源码：IcoTool[19]
介绍文章：Blazor在线Ico转换工具[20]
在线演示地址：https://tool.dotnet9.com/ico[21]
参考资料
[1]
IcoTool: https://github.com/dotnet9/dotnet9.com/blob/develop/src/Dotnet9.Tools.Web/Pages/Public/ImageTools/IcoTool.razor
[2]https://tool.dotnet9.com/ico: https://tool.dotnet9.com/ico
[3]MASA Blazor: https://masa-blazor-docs-dev.lonsid.cn/
[4]MFileInput: https://masa-blazor-docs-dev.lonsid.cn/components/file-inputs
[5]IcoTool.razor: https://github.com/dotnet9/dotnet9.com/blob/develop/src/Dotnet9.Tools.Web/Pages/Public/ImageTools/IcoTool.razor
[6]https://gist.github.com/darkfall/1656050: https://gist.github.com/darkfall/1656050
[7]ImagingHelper.cs: https://github.com/dotnet9/dotnet9.com/blob/develop/src/Dotnet9.Tools/Images/ImagingHelper.cs
[8]ImageHelperTests.cs: https://github.com/dotnet9/dotnet9.com/blob/develop/src/test/Dotnet9.Tools.Tests/Images/ImageHelperTests.cs
[9]IcoTool.razor: https://github.com/dotnet9/dotnet9.com/blob/develop/src/Dotnet9.Tools.Web/Pages/Public/ImageTools/IcoTool.razor
[10]ASP.NET Core Blazor file downloads: https://docs.microsoft.com/en-us/aspnet/core/blazor/file-downloads?view=aspnetcore-6.0
[11]_Layout.cshtml: https://github.com/dotnet9/dotnet9.com/blob/develop/src/Dotnet9.Tools.Web/Pages/_Layout.cshtml
[12]IcoTool.razor: https://github.com/dotnet9/dotnet9.com/blob/develop/src/Dotnet9.Tools.Web/Pages/Public/ImageTools/IcoTool.razor
[13]MASA Blazor: https://masa-blazor-docs-dev.lonsid.cn/
[14]7.0.100-preview.1: https://dotnet.microsoft.com/en-us/download/dotnet/7.0
[15].NET 6: https://dotnet.microsoft.com/en-us/download/dotnet/6.0
[16]Dotnet9.Tools: https://github.com/dotnet9/dotnet9.com
[17]提交issue: https://github.com/dotnet9/dotnet9.com/issues/new
[18]网站留言: https://dotnet9.com
[19]IcoTool: https://github.com/dotnet9/dotnet9.com/blob/develop/src/Dotnet9.Tools.Web/Pages/Public/ImageTools/IcoTool.razor
[20]Blazor在线Ico转换工具: https://dotnet9.com/?p=1715（在新窗口中打开）
[21]https://tool.dotnet9.com/ico: https://tool.dotnet9.com/ico
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