在silverlight SaveFileDialog中设置文件的内容类型

本文关键字：类型 文件 设置 silverlight SaveFileDialog | 更新日期: 2023-09-27 18:00:30

正如标题所说；是否有任何方法可以在Silverlight SaveFileDialog中设置文件的内容类型？我还没有找到办法，如果这不可能，我也不会感到惊讶，只是想问一下，看看是否有其他人确切知道。

在silverlight SaveFileDialog中设置文件的内容类型

您要查找的是上载文件的Mime类型。我想这在Silverlight中会起作用，我不明白为什么不起作用，但我从未在这种情况下使用过它。您需要添加以下内容：

using System.Reflection;
using System.Runtime.InteropServices;
[System.Runtime.InteropServices.DllImport(@"urlmon.dll", CharSet = CharSet.Auto)]
private extern static System.UInt32 FindMimeFromData(
    System.UInt32 pBC,
    [MarshalAs(UnmanagedType.LPStr)] System.String pwzUrl,
    [MarshalAs(UnmanagedType.LPArray)] byte[] pBuffer,
    System.UInt32 cbSize,
    [MarshalAs(UnmanagedType.LPStr)] System.String pwzMimeProposed,
    System.UInt32 dwMimeFlags,
    out System.UInt32 ppwzMimeOut,
    System.UInt32 dwReserverd
);
public void SomeMethod(string fileName)
{
    string mimeType = getMimeFromFile(fileName);
    if (mimeType == "text/plain")
{
        // do something
}
}
private string getMimeFromFile(string filename)
    {
        if (!File.Exists(filename))
            throw new FileNotFoundException(filename + " not found");
        byte[] buffer = new byte[256];
        using (FileStream fs = new FileStream(filename, FileMode.Open))
        {
            if (fs.Length >= 256)
                fs.Read(buffer, 0, 256);
            else
                fs.Read(buffer, 0, (int)fs.Length);
        }
        try
        {
            System.UInt32 mimetype;
            FindMimeFromData(0, null, buffer, 256, null, 0, out mimetype, 0);
            System.IntPtr mimeTypePtr = new IntPtr(mimetype);
            string mime = Marshal.PtrToStringUni(mimeTypePtr);
            Marshal.FreeCoTaskMem(mimeTypePtr);
            return mime;
        }
        catch (Exception ex)
        {
            return ex.Message;
        }
    }

 this.dialog = new SaveFileDialog();  
            try 
            {  
                this.dialog.DefaultExt = ".txt";  
                this.dialog.Filter = "Text Files|*.txt|Log Files|*.log|All Files|*.*";  
                this.dialog.FilterIndex = 2;  
            }  
            catch ( Exception ex )  
            {  
                this.tblError.Text = "Error configuring SaveFileDialog: " + ex.Message;  
            }
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