如何填充与被保存在数据库中的文件路径树状 [英] How to populate treeview with file path which is saved in database

问题描述

假如我有数据库中保存的文件路径。现在我想通过展示这些树状文件路径。我发现一个样本的工作正常，但不知道什么时候会有巨大的数据库数据，那么树形视图人口将被挂起或花费太长时间。在这里我给的代码。请检查并告诉它可以纠正，结果表现将好时，会有分贝巨大的数据。

suppose i have saved file path in database. now i want to show those file path through treeview. i found one sample that works fine but do not know when there will be huge data in database then treeview population will be hang or take too long. here i am giving the code. please check and tell which can be rectified as a result performance will be good when there will be huge data in db.

public static class MyDataBase
{
    private static List<string> fields = new List<string>();

    public static void AddField(string field)
    {
        fields.Add(field);
    }

    public static IList<string> FieldsInMyColumn()
    {
        return fields;
    }
}

public void CreateTreeView()
    {
        foreach (string field in MyDataBase.FieldsInMyColumn())
        {
            string[] elements = field.Split('\\');
            TreeNode parentNode = null;

            for (int i = 0; i < elements.Length - 1; ++i)
            {
                if (parentNode == null)
                {
                    bool exits = false;
                    foreach (TreeNode node in myTreeview.Nodes)
                    {
                        if (node.Text == elements[i])
                        {
                            exits = true;
                            parentNode = node;
                        }
                    }

                    if (!exits)
                    {
                        TreeNode childNode = new TreeNode(elements[i]);
                        myTreeview.Nodes.Add(childNode);
                        parentNode = childNode;
                    }
                }
                else
                {
                    bool exits = false;
                    foreach (TreeNode node in parentNode.Nodes)
                    {
                        if (node.Text == elements[i])
                        {
                            exits = true;
                            parentNode = node;
                        }
                    }

                    if (!exits)
                    {
                        TreeNode childNode = new TreeNode(elements[i]);
                        parentNode.Nodes.Add(childNode);
                        parentNode = childNode;
                    }
                }
            }

            if (parentNode != null)
            {
                parentNode.Nodes.Add(elements[elements.Length - 1]);
            }
        }
    }

 private void button1_Click(object sender, EventArgs e)
    {
        MyDataBase.AddField(@"c:\jsmith\project1\hello.cs");
        MyDataBase.AddField(@"c:\jsmith\project1\what.cs");
        MyDataBase.AddField(@"c:\jsmith\project2\hello.cs");
        MyDataBase.AddField(@"c:\jsmith\project1\tdp.cs");
        MyDataBase.AddField(@"c:\jsmith\project2\ship.cs");
        MyDataBase.AddField(@"d:\jsmith\project1\hello404.cs");
        MyDataBase.AddField(@"c:\jsmith1\project2\ship.cs");
        CreateTreeView();
    }

感谢

thanks

推荐答案

根据您的框架版本，也许你可以尝试这样的事：

Depending on your framework version, maybe you can try something like this :

public void ProcessPath(IEnumerable<String> path,  TreeNodeCollection nodes)
{
    if (!path.Any())
        return;
    var node = nodes.Cast<TreeNode>().FirstOrDefault(n => n.Text == path.First());
    if (node == null)
    {
        node = new TreeNode(text: path.First());
        nodes.Add(node);
    }
    ProcessPath(path.Skip(1),node.ChildNodes);
}

public void CreateTreeView()
{
    foreach (string field in MyDataBase.FieldsInMyColumn())
        ProcessPath(field.Split('\\'),myTreeView.Nodes);
}

如果你真的有一个巨大的行数量，你应该寻找一个解决方案，其中只一个节点

If you really have a huge amount of rows, you should probably look for a solution where you only load the child nodes upon click on a node

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