[C#]DropBox開發系列 - 使用DropNet下載DropBox內存放的檔案

要使用DropNet下載DropBox內存放的檔案，我們可以透過DropNetClient.GetFile來做，將我們想要下載的檔案位置帶入該函式，會將指定檔案的內容回傳，因此成式撰寫起來會像下面這樣： … var selectedNode = treeView1.SelectedNode; if (selectedNode == null) return;

		var metaData = selectedNode.Tag as MetaData;
		if(metaData == null)
			return;

		using (var saveFileDialog = new SaveFileDialog())
		{
			saveFileDialog.FileName = metaData.Name;

			if(saveFileDialog.ShowDialog() == DialogResult.OK)
			{
				var fileData = m_DropNetClient.GetFile(metaData.Path);
				File.WriteAllBytes(saveFileDialog.FileName, fileData);
			}
		}
		...

實際運作起來會像下面這樣，假設我嚐試要抓取的是Batch目錄下的Close.bat檔。

下載時會先詢問要存放的檔案位置，這邊為了方便就先將檔案放在桌面上。

按下儲存後桌面上會有我們剛剛所選取的檔案，將檔案開起來查驗，可以看到檔案確確實實的下載下來了。

筆者在撰寫時為了方便都是以同步的方式下去做說明，實際使用時若有需要可以考慮用非同步的方式叫用，將程式改呼叫GetFileAsync就可以了。

最後一樣附上完整的使用範例：

using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using DropNet; using DropNetDemo.Properties; using DropNet.Models; using System.IO;

namespace DropNetDemo { public partial class Form1 : Form { #region Var private DropNetClient _dropNetClient; #endregion

	#region Private Property
	private DropNetClient m_DropNetClient
	{
		get
		{
			return _dropNetClient ?? (_dropNetClient = new DropNetClient(tbxAppKey.Text, tbxAppSecret.Text));
		}
		set
		{
			_dropNetClient = value;
		}
	}
	#endregion

	public Form1()
	{
		InitializeComponent();
	}

	private void SetSecretAndToken(string secret, string token)
	{
		Settings.Default.SECRET = secret;
		Settings.Default.TOKEN = token;
	}

	private void btnLogin_Click(object sender, EventArgs e)
	{
		if (!String.IsNullOrEmpty(Properties.Settings.Default.SECRET) && !String.IsNullOrEmpty(Properties.Settings.Default.TOKEN))
		{
			m_DropNetClient.UserLogin = new UserLogin()
			{
				Secret = Properties.Settings.Default.SECRET,
				Token = Properties.Settings.Default.TOKEN
			};

			FillTreeView();
			return;
		}

		var callbackUrl = "https://www.dropbox.com/1/oauth/authorize";
		var cancelCallbackUrl = "https://www.dropbox.com/home";
		var size = new Size(1024, 600);

		if (DoOAuth(callbackUrl, cancelCallbackUrl, size) == DialogResult.OK)
		{
			var accessToken = m_DropNetClient.GetAccessToken();
			Properties.Settings.Default.SECRET = accessToken.Secret;
			Properties.Settings.Default.TOKEN = accessToken.Token;
			Properties.Settings.Default.Save();

			FillTreeView();
		}
	}

	private void FillTreeView()
	{
		treeView1.Nodes.Clear();
		var metaData = m_DropNetClient.GetMetaData("/");

		FillDirOrFileToTreeView(null, metaData);
	}

	private void FillDirOrFileToTreeView(TreeNode parentNode, MetaData metaData)
	{
		if (metaData.Contents == null)
			return;

		var nodes = (parentNode == null) ? treeView1.Nodes : parentNode.Nodes;
		try
		{
			treeView1.BeginUpdate();
			foreach (var childMetaData in metaData.Contents)
			{
				if (childMetaData.Is_Dir)
				{
					var node = nodes.Add(childMetaData.Name);
					node.Tag = childMetaData;
					node.Nodes.Add(string.Empty);
				}
				else
				{
					nodes.Add(childMetaData.Name).Tag = childMetaData;
				}
			}
		}
		finally
		{
			treeView1.EndUpdate();
		}
	}

	private void treeView1_BeforeExpand(object sender, TreeViewCancelEventArgs e)
	{
		var node = e.Node;

		if (!(node.Nodes.Count == 1 && node.Nodes[0].Tag == null))
			return;

		node.Nodes.Clear();

		FillDirOrFileToTreeView(node, m_DropNetClient.GetMetaData("/" + node.FullPath));
	}

	private DialogResult DoOAuth(string callbackUrl, string cancelCallbackUrl, System.Drawing.Size size)
	{
		using (var dialog = new Form())
		{
			var browesr = new WebBrowser()
			{
				Dock = DockStyle.Fill
			};

			var token = m_DropNetClient.GetToken();
			var authUrl = m_DropNetClient.BuildAuthorizeUrl();
			browesr.Navigated += (s, ex) =>
			{
				var url = ex.Url.ToString();
				if (url.Equals(callbackUrl))
				{
					dialog.DialogResult = DialogResult.OK;
				}
				else if (url.Equals(cancelCallbackUrl))
				{
					dialog.DialogResult = DialogResult.Cancel;
				}
			};
			browesr.Navigate(authUrl);

			dialog.Size = size;
			dialog.Controls.Add(browesr);

			return dialog.ShowDialog();
		}
	}

	private void tbxAppKey_TextChanged(object sender, EventArgs e)
	{
		m_DropNetClient = null;
	}

	private void tbxAppSecret_TextChanged(object sender, EventArgs e)
	{
		m_DropNetClient = null;
	}

	private void treeView1_MouseDoubleClick(object sender, MouseEventArgs e)
	{
		var selectedNode = treeView1.SelectedNode;
		if (selectedNode == null)
			return;

		var metaData = selectedNode.Tag as MetaData;
		if(metaData == null)
			return;

		using (var saveFileDialog = new SaveFileDialog())
		{
			saveFileDialog.FileName = metaData.Name;

			if(saveFileDialog.ShowDialog() == DialogResult.OK)
			{
				var fileData = m_DropNetClient.GetFile(metaData.Path);
				File.WriteAllBytes(saveFileDialog.FileName, fileData);
			}
		}
	}
}

}