C#如何使用treeView列出目录和子目录而不显示根目录?

问题描述：

来自

main folder
|_a
| |_b
| |_c
|_d
|_e

到

a
 |_b
 |_c
d
e

我想要一个没有主文件夹的树状视图.我找到了一个解决方案在这里，但它似乎非常慢.当我第一次启动程序时，加载它需要一分钟多的时间.如果没有该代码，它会立即打开.

I want a treeview without the main folder. I found a solution here but it seems that it's incredibly slow. When I first start the program it takes over a minute to load it. Without that code it opens instantly.

那么，您知道为什么要改进此代码或其他更好的代码吗?

So, do you know any why to improve this code or another better code?

已解决.

答

试试这个，这里看起来真的很快.您可以控制是否扩展所有节点..您需要包含 LINQ namspace (using System.Linq;)

Try this, it looks real fast here. You can control whether all nodes are expanded or not.. You need to included the LINQ namspace (using System.Linq;)

// somewhere:
string yourRoot = "D:\\";
treeView1.Nodes.AddRange(getFolderNodes(yourRoot, true).ToArray());

private void treeView1_BeforeExpand(object sender, TreeViewCancelEventArgs e)
{
    TreeNode tn = e.Node.Nodes[0];
    if (tn.Text == "...")
    {
        e.Node.Nodes.AddRange(getFolderNodes(((DirectoryInfo)e.Node.Tag)
              .FullName, true).ToArray());
        if (tn.Text == "...") tn.Parent.Nodes.Remove(tn);
    }
}

List<TreeNode> getFolderNodes(string dir, bool expanded)
{
    var dirs = Directory.GetDirectories(dir).ToArray();
    var nodes = new List<TreeNode>();
    foreach (string d in dirs)
    {
        DirectoryInfo di = new DirectoryInfo(d);
        TreeNode tn = new TreeNode(di.Name);
        tn.Tag = di;
        int subCount = 0;
        try { subCount = Directory.GetDirectories(d).Count();  } 
        catch { /* ignore accessdenied */  }
        if (subCount > 0) tn.Nodes.Add("...");
        if (expanded) tn.Expand();   //  **
        nodes.Add(tn);
    }
    return nodes;
}

如果你确定你总是想从一开始就看到所有级别的展开，你可以使用这个功能并删除BeforeExpand代码:

If you are sure you always want to see all levels expaded from the start you can use this function and delete the BeforeExpand code:

List<TreeNode> getAllFolderNodes(string dir)
{
    var dirs = Directory.GetDirectories(dir).ToArray();
    var nodes = new List<TreeNode>();
    foreach (string d in dirs)
    {
        DirectoryInfo di = new DirectoryInfo(d);
        TreeNode tn = new TreeNode(di.Name);
        tn.Tag = di;
        int subCount = 0;
        try { subCount = Directory.GetDirectories(d).Count(); } 
        catch { /* ignore accessdenied */  }
        if (subCount > 0)
        {
            var subNodes = getAllFolderNodes(di.FullName);
            tn.Nodes.AddRange(subNodes.ToArray());
        }
        nodes.Add(tn);
    }
    return nodes;
}

你像以前一样称呼它:

string yourRoot = "D:\\";
Cursor.Current = Cursors.WaitCursor;
treeView1.Nodes.AddRange(getAllFolderNodes(yourRoot).ToArray());
Cursor.Current = Cursors.Default;

C#如何使用treeView列出目录和子目录而不显示根目录?

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