[C＃Cefsharp在右键单击图像时下载图像

Question

[当前，在我的浏览器中，当您右键单击任何内容以及图像时，您只会得到以下内容：

但是我也想要一个保存图像按钮，甚至可以复制链接地址或复制图像。我该怎么办？

Answer 1

Carlos Delgado在ourcodeworld.com上有一篇精彩的文章，其中介绍了如何修改上下文菜单：

https://ourcodeworld.com/articles/read/449/how-to-add-new-items-to-the-native-context-menu-on-a-cefsharp-control-in-winforms

我用他的示例将这些项目添加到上下文菜单：

public class MyCustomMenuHandler : IContextMenuHandler
{
public void OnBeforeContextMenu(IWebBrowser browserControl, IBrowser browser, IFrame frame, IContextMenuParams parameters, IMenuModel model)
{
    // Remove any existent option using the Clear method of the model
    //
    //model.Clear();

    Console.WriteLine("Context menu opened !");

    // You can add a separator in case that there are more items on the list
    if (model.Count > 0)
    {
        model.AddSeparator();
    }


    // Add a new item to the list using the AddItem method of the model

    model.AddItem((CefMenuCommand)26501, "Show DevTools");

    // Add a separator
    model.AddSeparator();


    model.AddItem((CefMenuCommand)26503, "Open in Paintbrush");
    model.AddItem((CefMenuCommand)26504, "Open in Excel");
    model.AddItem((CefMenuCommand)26505, "Run Script..");

......等

然后删除了查看源代码选项：

model.Remove((CefMenuCommand)132); // View Source

然后只是为了好玩而加入了这些选项，这些选项默认情况下不在菜单中：

    model.AddItem((CefMenuCommand)113, "Copy"); 
    model.AddItem((CefMenuCommand)100, "Back"); 
    model.AddItem((CefMenuCommand)101, "Forward"); 
    model.AddItem((CefMenuCommand)102, "Reload"); 
    model.AddItem((CefMenuCommand)103, "Reload No Cache"); 
    model.AddItem((CefMenuCommand)131, "Print"); 

然后玩得开心

public void SaveImage(string imageUrl, string filename, ImageFormat format)
{
    System.Net.WebClient client = new WebClient();
    System.IO.Stream stream = client.OpenRead(imageUrl);
    Bitmap bitmap; bitmap = new Bitmap(stream);

    if (bitmap != null)
    {
        bitmap.Save(filename, format);
    }

    stream.Flush();
    stream.Close();
    client.Dispose();
}


public bool OnContextMenuCommand(IWebBrowser browserControl, IBrowser browser, IFrame frame, IContextMenuParams parameters, CefMenuCommand commandId, CefEventFlags eventFlags)
{
    if (commandId == (CefMenuCommand)26501)
    {
        browser.GetHost().ShowDevTools();
        return true;
    }

    if (commandId == (CefMenuCommand)26502)
    {
        browser.GetHost().CloseDevTools();
        return true;
    }

    if (commandId == (CefMenuCommand)113) // Copy
    {

        if (parameters.LinkUrl.Length > 0)
        {
            Clipboard.SetText(parameters.LinkUrl);
        }
        if (parameters.MediaType == ContextMenuMediaType.Image )
        {
            Clipboard.SetText(parameters.SourceUrl);
        }



    }

    if (commandId == (CefMenuCommand)26503) // Open in paintbrush
    {

        if (parameters.LinkUrl.Length > 0) {

            Clipboard.SetText(parameters.LinkUrl);

        }
        if (parameters.MediaType == ContextMenuMediaType.Image)
        {
            Clipboard.SetText(parameters.SourceUrl);

            string subPath = @"C:\temp";

            string fn = @"C:\temp\temp.bmp";

            System.IO.Directory.CreateDirectory(subPath);

            SaveImage(parameters.SourceUrl, fn, ImageFormat.Bmp);

            Process.Start(fn);

        }
    }



    // React to the third ID (Display alert message)
    if (commandId == (CefMenuCommand)26503)
    {
        MessageBox.Show("An example alert message ?");
        return true;
    }

    // Any new item should be handled through a new if statement


    // Return false should ignore the selected option of the user !
    return false;
}