我这里的控件为一个ListBox。代码如下：
Public Class Form1
Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load
Me.ListBox1.AllowDrop = True
End Sub
Private Sub ListBox1_DragEnter(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles ListBox1.DragEnter
Dim o As Object = e.Data.GetData(DataFormats.FileDrop)
If Not o Is Nothing Then
e.Effect = DragDropEffects.Copy
End If
End Sub
Private Sub ListBox1_DragDrop(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles ListBox1.DragDrop
Dim FileNames As String() = CType(e.Data.GetData(DataFormats.FileDrop), String())
Me.ListBox1.Items.AddRange(FileNames)
End Sub
End Class重写这个HOW TO，主要的是看到有人用API实现，代码如下：
VB.NET：
Public Class Form1
Private Const WM_DropFILES As Integer = 563
Private Declare Function DragAcceptFiles Lib "shell32.dll" (ByVal hwnd As IntPtr, ByVal accept As Boolean) As Long
Private Declare Function DragQueryFile Lib "shell32.dll" (ByVal hDrop As IntPtr, ByVal file As Integer, ByVal fileName As System.Text.StringBuilder, ByVal size As Int32) As Int32
Private Declare Sub DragFinish Lib "Shell32.dll" (ByVal hDrop As IntPtr)
Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)
If m.Msg = WM_DropFILES Then
Dim iNumOfFiles As Int32 = DragQueryFile(m.WParam, &HFFFFFFFF, Nothing, 0)
Dim iPnt As Int32
For iPnt = 0 To iNumOfFiles - 1
Dim sb As New System.Text.StringBuilder(256)
Dim iRet As Int32 = DragQueryFile(m.WParam, iPnt, sb, sb.Capacity)
ListBox1.Items.Add(sb.ToString)
Next
DragFinish(m.WParam)
Else
MyBase.WndProc(m)
End If
End Sub
Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load
DragAcceptFiles(ListBox1.Handle, True)
End Sub
End ClassC#：
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
const int WM_DropFILES = 563;
[DllImport("shell32.dll")]
private static extern long DragAcceptFiles(IntPtr hwnd, bool accept);
[DllImport("shell32.dll")]
private static extern int DragQueryFile(IntPtr hDrop, int file, StringBuilder fileName, int size);
[DllImport("shell32.dll")]
private static extern void DragFinish(IntPtr hDrop);
protected override void WndProc(ref Message m)
{
if (m.Msg == WM_DropFILES)
{
int iNumOfFiles = DragQueryFile(m.WParam, -1, null, 0);
int iPnt;
for (iPnt = 0; iPnt < iNumOfFiles; iPnt++)
{
StringBuilder sb = new StringBuilder(256);
int iRet = DragQueryFile(m.WParam, iPnt, sb, sb.Capacity);
listBox1.Items.Add(sb.ToString());
}
DragFinish(m.WParam);
}
else
{
base.WndProc(ref m);
}
}
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
DragAcceptFiles(listBox1.Handle, true);
}
}
}
评论（0）
暂无评论。