拖拽放下怎么样？ [英] Drag & Drop how to?

问题描述

我正在创建一个简单的拖拽和应用程序下降。我正在使用Windows 10操作系统，Visual Studio 2015&使用c＃创建Windows应用程序。

我在表单上添加了面板。对于面板，AllowDrop为true。

我在Panel的事件窗口中添加了3个事件：private void panel1_DragEnter（object sender，DragEventArgs e）

         {

            e.Effect = DragDropEffects.All;

        }


        private void panel1_DragOver（object sender，DragEventArgs e）

        {

            e.Effect = DragDropEffects.All;

        }
private void panel1_DragDrop（object sender，DragEventArgs e）

        {
$


        }


但它不允许我在这里删除文件。请告诉我代码有什么问题。

---

G Goyal

Hi,

I am creating a simple application for drag & drop. I am using Windows 10 OS, Visual Studio 2015 & creating windows application using c#.
I have added panel on the form. AllowDrop is true for the panel.
I have added 3 events from event windows for Panel : private void panel1_DragEnter(object sender, DragEventArgs e)
        {
            e.Effect = DragDropEffects.All;
        }

        private void panel1_DragOver(object sender, DragEventArgs e)
        {
            e.Effect = DragDropEffects.All;
        }
private void panel1_DragDrop(object sender, DragEventArgs e)
        {

        }

But it is not allowing me to drop files here. Please let me know what is wrong with the code.

---

G Goyal

推荐答案

嗨Goyal，

Hi Goyal,

Panel是一个容器控件，用于放置一些其他控件，如果你想将一些文件拖到窗体中，那么如何使用ListBox呢？

Panel is a container control used to place some of another controls, if you want to drag some files to the form, how about to use ListBox instead?

我做了一个简单的使用ListBox演示，你可以参考如下：

I made a simple demo with ListBox, you can refer to it as below:

    public partial class Form3 : Form
    {
        public Form3()
        {
            InitializeComponent();
        }
        public string FilePath;

        private void Form3_Load(object sender, EventArgs e)
        {
            listBox1.AllowDrop = true;
        }

        private void listBox1_DragEnter(object sender, DragEventArgs e)
        {
            if (e.Data.GetDataPresent(DataFormats.FileDrop))
            {
                e.Effect = DragDropEffects.All;
            }
            else
            {
                e.Effect = DragDropEffects.None;
            }
        }

        private void listBox1_DragDrop(object sender, DragEventArgs e)
        {
            string[] s = (string[])e.Data.GetData(DataFormats.FileDrop, false);

            for (int i = 0; i < s.Length; i++)
            {
                listBox1.Items.Add(s[i]);
            }
        }

        //open the file when select one
        private void button1_Click(object sender, EventArgs e)
        {
            string filePath = GetListBoxItem();

            if (!string.IsNullOrEmpty(filePath))
            {
                System.Diagnostics.Process.Start(filePath);
            }
        }

        //get item
        public string GetListBoxItem()
        {
            string filePath = string.Empty;

            bool isSelected = IsListBoxSelected();

            if (isSelected == true)
            {
                string listBoxItemValue = listBox1.SelectedItem.ToString();

                filePath = listBoxItemValue;
            }
            else
            {
                MessageBox.Show("ListBox must be selected.");
            }

            return filePath;
        }

        //determine if select a file
        public bool IsListBoxSelected()
        {
            bool selected;

            if (listBox1.SelectedIndex == -1)
            {
                selected = false;
            }
            else
            {
                selected = true;
            }

            return selected;
        }
    }

问候，

Stanly

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