C#實現base64 字符串轉文件存儲

把一個base64 字符串解碼后存為另外一個文件

void Main()
{
    ConvertFromBase64String();
}

void ConvertFromBase64String()
{
    string fileName = GetSaveFileName();
    if ( fileName == null )
    {
        MessageBox.Show("No file name specified");
    }
    else
    {
        ConvertFromBase64String(fileName);
    }
}

void ConvertFromBase64String(string saveFileName)
{
    ConvertFromBase64String(Clipboard.GetText(), saveFileName);
}

void ConvertFromBase64String(string input, string saveFileName)
{
    var contents = Convert.FromBase64String(input);

    using (var fs = new FileStream(saveFileName, FileMode.Create, FileAccess.Write))
    {
        fs.Write(contents, 0, contents.Length);
        fs.Flush();
    }
}

string GetFileName(FileDialog fd)
{
    bool? result = fd.ShowDialog();
    if ( result != null && result.Value )
    {
        return fd.FileName;
    }
    return null;
}

string GetOpenFileName()
{
    var ofd = new OpenFileDialog { Title = "Select text file", Filter = "All files (*.*)|*.*",
        RestoreDirectory = true };
    return GetFileName(ofd);
}

string GetSaveFileName()
{
    var sfd = new SaveFileDialog { Title = "Save file as", Filter = "All files (*.*)|*.*",
        RestoreDirectory = true };
    return GetFileName(sfd);
}