C#.NET中管理文件（磁盘和目录的管理）

       前 几天在写毕业设计，使用的是C#.NET。其中遇到要浏览文件夹问题，因为本来就是要做论文才看的C#.NET的，所以还真是不知道怎么做。查阅了书，看到了怎么访问磁盘和目录，帮我解决了问题，但是代码有点多。后来看到一同学用了一控键实现了，而且就四条代码，晕！ 先说第一种自定义的，再说使用控键的。

 初始化控件
    类Directory封装了访问及操作磁盘和目录的方法。使用Directory类需要在类DirectoryDialog的声明之前加入对System.IO名字空间的应用。在类的DirectoryDialog的构造方法中初始化控件。这里要把本地所有的磁盘列在ComboBox控件中并在TreeView控件中显示第一个磁盘的目录下的所有目录。

public DirectoryDialog()
        {
            InitializeComponent();
            String[] drivers = null;
            try
            {
                drivers = Directory.GetLogicalDrives();
            }

            catch (Exception excep)
            {
                MessageBox.Show(excep.Message, "false",  MessageBoxButtons.OK);
                return;
            }
            int CDriverIndex = 0;
            for (int i = 0; i < drivers.Length; i++)
            {
                comboBox1.Items.Add(drivers[i]);
                if (drivers[i].Equals("C://") || drivers[i].Equals("C://"))
                {
                    CDriverIndex = i;
                }

            }
            path = drivers[CDriverIndex];
            comboBox1.SelectedIndex = CDriverIndex;
            TreeNode node = new TreeNode(path);
            node.ImageIndex = 0;
            node.SelectedImageIndex = 0;
            treeView1.Nodes.Add(node);
            string[] dirs = null;
            try
            {
                dirs = Directory.GetDirectories(path);
            }
            catch (Exception excep)
            {
                MessageBox.Show(excep.Message, "false", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
            for (int i = 0; i < dirs.Length; i++)
            {
                int lastIndex = dirs[i].LastIndexOf("//");
                node = new TreeNode(dirs[i].Substring(lastIndex + 1));
                node.ImageIndex = 1;
                node.SelectedImageIndex = 1;
                treeView1.Nodes[0].Nodes.Add(node);
            }
        }
实现ComboBox控件的事件方法
    当用户打开ComboBox的下拉列表，作选择之后再关闭下拉列表时，ComboBox控件就会发SelectedIndexChanged事件。

 private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            path = comboBox1.SelectedItem.ToString();
            treeView1.Nodes.Clear();
            TreeNode node = new TreeNode(path);
            node.ImageIndex = 0;
            node.SelectedImageIndex = 0;
            treeView1.Nodes.Add(node);
            String[] dirs = null;
            try
            {
                dirs = Directory.GetDirectories(path);
            }
            catch(Exception excep)
            {
                MessageBox.Show(excep.Message, "false", MessageBoxButtons.OK, MessageBoxIcon.Error);
                return;
            }
            for(int i=0;i<dirs.Length;i++)
            {
                int lastIndex=dirs[i].LastIndexOf("//");
                node=new TreeNode(dirs[i].Substring(lastIndex+1));
                node.ImageIndex=1;
                node.SelectedImageIndex=1;
                treeView1.Nodes[0].Nodes.Add(node);
            }
        }

实现TreeView控件的事件方法
当用户要展开某个磁盘或目录时，需要初始化这个磁盘或目录中的所有子目录下的子目录，这需要实现TreeeView的BeforeExpand事件方法。在目录展开之后，需要更改节点的图标，这需要实现TreeeView 的AfterExpand事件方法。在目录折叠之后，也需要更改节点的图标，这需要实现TreeeView的AfterCollapse事件方法。当用户选择一个目录时，需要记录用户的选择，这需要实现TreeeView的AfterSelect事件方法。

 private void treeView1_BeforeExpand(object sender, TreeViewCancelEventArgs e)
        {
            String fullPath;
            if (e.Node.Equals(treeView1.Nodes[0]))
            {
                fullPath = "";
            }
            else
            {
                fullPath = e.Node.Text + "//";
            }
            TreeNode tempNode = e.Node;
            while (tempNode.Parent != null && !tempNode.Parent.Equals(treeView1.Nodes[0]))
            {
                fullPath = tempNode.Parent.Text + "//" + fullPath;
                tempNode = tempNode.Parent;
            }
            fullPath = treeView1.Nodes[0].Text + fullPath;
            for (int i = 0; i < e.Node.Nodes.Count; i++)
            {
                String[] dirs = null;
                try
                {
                    dirs = Directory.GetDirectories(fullPath + e.Node.Nodes[i].Text);
                }
                catch (Exception excep)
                {
                    MessageBox.Show(excep.Message, "false", MessageBoxButtons.OK, MessageBoxIcon.Error);
                    break;
                }
                e.Node.Nodes[i].Nodes.Clear();
                for (int j = 0; j < dirs.Length; j++)
                {
                    int lastIndex = dirs[j].LastIndexOf("//");
                    TreeNode newNode = new TreeNode(dirs[j].Substring(lastIndex + 1));
                    newNode.ImageIndex = 1;
                    newNode.SelectedImageIndex = 1;
                    e.Node.Nodes[i].Nodes.Add(newNode);
                }
            }

      }

 private void treeView1_AfterExpand(object sender, TreeViewEventArgs e)
        {
            if (!e.Node.Equals(treeView1.Nodes[0]))
            {
                e.Node.ImageIndex = 2;
                e.Node.SelectedImageIndex = 2;
            }

        }

        private void treeView1_AfterCollapse(object sender, TreeViewEventArgs e)
        {
            if (!e.Node.Equals(treeView1.Nodes[0]))
            {
                e.Node.ImageIndex = 1;
                e.Node.SelectedImageIndex = 1;
            }
        }
 private void treeView1_AfterSelect(object sender, TreeViewEventArgs e)
        {
            if (e.Node.Equals(treeView1.Nodes[0]))
            {
                path = "";
            }
            else
            {
                path = e.Node.Text + "//";
            }
            TreeNode tempNode = e.Node;
            while (tempNode.Parent != null && !tempNode.Parent.Equals(treeView1.Nodes[0]))
            {
                path = tempNode.Parent.Text + "//" + path;
                tempNode = tempNode.Parent;
            }
            path = treeView1.Nodes[0].Text + path;
        }

使用对话框
前面已经实现了一个可以浏览磁盘和目录的对话框，这里要在主窗体中显示这个对话框，并获取所选择的目录。使用这个对话框的代码位于按钮的点击事件方法中。

 private void button1_Click(object sender, EventArgs e)
        {
            DirectoryDialog ddlg = new DirectoryDialog();
            if (ddlg.ShowDialog() == DialogResult.OK)
            {
                textBox1.Text = ddlg.selectedPath;
            }
        }

        上面的方法是自定义浏览对话框，在TreeView中还记得添加图标。如文件夹和磁盘图标。上面太麻烦，如过使用folderBrowserDialog控键就简单多了。只需要一按钮、一 textbox控件就可以了。代码如下：

 private void button1_Click(object sender, EventArgs e)
        {
            String basePath;
            folderBrowserDialog1.ShowNewFolderButton = true;
            folderBrowserDialog1.ShowDialog();
            textBox1.Text = folderBrowserDialog1.SelectedPath;
            basePath = folderBrowserDialog1.SelectedPath;
        }