是否可以在InputBox上使用intellisense

为了使用"Intellisense"（我猜您的意思是"自动完成"），您可以简单地设置TextBox并分配其AutoComplete...属性。您特别需要的是：

1. AutoCompleteCustomSource-它只是一个集合，因此您可以添加自己的字符串列表用作源。这样，如果您不想这样做，就不必担心DataSet或任何类型的数据库访问
2. 自动完成模式-它告诉控件应该是什么类型的自动完成输入框
3. AutoCompleteSource-在您的情况下，如果您使用#1作为解决方案，您会将其设置为CustomSource

编辑

例如：

textBox1.AutoCompleteMode = AutoCompleteMode.Suggest;
textBox1.AutoCompleteSource = AutoCompleteSource.CustomSource;
AutoCompleteStringCollection items = new AutoCompleteStringCollection();
items.Add("Save");
items.Add("Don't Save");
textBox1.AutoCompleteCustomSource = items;

编辑2

根据要求，以下是如何逐行读取文本文件，并将其中的数据用作AutoComplete 的自定义源

string line = "";
AutoCompleteStringCollection items = new AutoCompleteStringCollection();
// Read the file and display it line by line.
System.IO.StreamReader file = new System.IO.StreamReader("YOURFILE.txt");
while((line = file.ReadLine()) != null)
{
    if(!String.IsNullOrEmpty(line))
    {
        items.Add(line);
    }
}
file.Close();

希望这能有所帮助！

这是可能的，需要相当多的代码。也许写你自己的控件更好。

using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Windows.Forms;
namespace Namespace {
public static class InputBoxEx {
    [STAThread]
    static void Main() {
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        Form f = new Form();
        Button b = new Button { Text = "Button" };
        f.Controls.Add(b);
        b.Click += delegate {
            String[] words = new[] { "apple", "banana", "carrot" };
            InputBoxEx.ShowInputBox("Prompt", "Title", "Default", -1, -1, words);
        };
        Application.Run(f);
    }
    private static IntPtr hHook = IntPtr.Zero;
    private const int WH_CALLWNDPROCRET = 12;
    private delegate IntPtr HookProc(int nCode, IntPtr wParam, IntPtr lParam);
    private static HookProc hookProc = new HookProc(InputBoxHookProc);
    private static String[] autoCompleteWords = null;
    public static String ShowInputBox(String prompt, String title, String defaultResponse, int xPos = -1, int yPos = -1, String[] autoCompleteWords = null) {
        init(autoCompleteWords);
        return Microsoft.VisualBasic.Interaction.InputBox(prompt, title, defaultResponse, xPos, yPos);
    }
    private static void init(String[] autoCompleteWords) {
        if (hHook != IntPtr.Zero)
            throw new Exception("Cannot be called by multiple threads.");
        InputBoxEx.autoCompleteWords = autoCompleteWords;
        int processID = GetCurrentThreadId();
        hHook = SetWindowsHookEx(WH_CALLWNDPROCRET, hookProc, IntPtr.Zero, processID);
    }
    // returns true if a TextBox is found
    private static bool assignAutoCompleteWords(IntPtr main) {
        List<IntPtr> ptr = GetChildWindows(main);
        foreach (IntPtr p in ptr) {
            TextBox c = Control.FromHandle(p) as TextBox;
            if (c == null)
                continue;
            c.AutoCompleteMode = AutoCompleteMode.SuggestAppend;
            c.AutoCompleteSource = AutoCompleteSource.CustomSource;
            c.AutoCompleteCustomSource.AddRange(autoCompleteWords);
            return true;
        }
        return false;
    }
    private enum CbtHookAction : int {
        HCBT_MOVESIZE = 0,
        HCBT_MINMAX = 1,
        HCBT_QS = 2,
        HCBT_CREATEWND = 3,
        HCBT_DESTROYWND = 4,
        HCBT_ACTIVATE = 5,
        HCBT_CLICKSKIPPED = 6,
        HCBT_KEYSKIPPED = 7,
        HCBT_SYSCOMMAND = 8,
        HCBT_SETFOCUS = 9
    }
    [StructLayout(LayoutKind.Sequential)]
    public struct CWPRETSTRUCT {
        public IntPtr lResult;
        public IntPtr lParam;
        public IntPtr wParam;
        public uint message;
        public IntPtr hwnd;
    };
    private static IntPtr InputBoxHookProc(int nCode, IntPtr wParam, IntPtr lParam) {
        if (nCode < 0) {
            return CallNextHookEx(hHook, nCode, wParam, lParam);
        }
        CWPRETSTRUCT msg = (CWPRETSTRUCT) Marshal.PtrToStructure(lParam, typeof(CWPRETSTRUCT));
        IntPtr hook = hHook;
        if (msg.message == (int) CbtHookAction.HCBT_ACTIVATE) {
            bool unhook = false;
            try {
                unhook = assignAutoCompleteWords(msg.hwnd);
            } catch {
                unhook = true;
            }
            if (unhook) {
                UnhookWindowsHookEx(hHook);
                hHook = IntPtr.Zero;
            }
        }
        return CallNextHookEx(hook, nCode, wParam, lParam);
    }
    [DllImport("user32.dll")]
    private static extern IntPtr SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hInstance, int threadId);
    [DllImport("user32.dll")]
    private static extern int UnhookWindowsHookEx(IntPtr idHook);
    [DllImport("user32.dll")]
    private static extern IntPtr CallNextHookEx(IntPtr idHook, int nCode, IntPtr wParam, IntPtr lParam);
    [DllImport("user32.dll")]
    private static extern bool EnumThreadWindows(int dwThreadId, EnumThreadDelegate lpfn, IntPtr lParam);
    private delegate bool EnumThreadDelegate(IntPtr hWnd, IntPtr lParam);
    [DllImport("kernel32.dll")]
    private static extern int GetCurrentThreadId();
    [DllImport("user32.Dll")]
    private static extern bool EnumChildWindows(IntPtr parentHandle, Win32Callback callback, IntPtr lParam);
    private delegate bool Win32Callback(IntPtr hwnd, IntPtr lParam);
    private static List<IntPtr> GetChildWindows(IntPtr parent) {
        List<IntPtr> result = new List<IntPtr>();
        GCHandle listHandle = GCHandle.Alloc(result);
        try {
            Win32Callback childProc = new Win32Callback(EnumWindow);
            EnumChildWindows(parent, childProc, GCHandle.ToIntPtr(listHandle));
        } finally {
            if (listHandle.IsAllocated)
                listHandle.Free();
        }
        return result;
    }
    private static bool EnumWindow(IntPtr handle, IntPtr pointer) {
        GCHandle gch = GCHandle.FromIntPtr(pointer);
        List<IntPtr> list = gch.Target as List<IntPtr>;
        if (list == null)
            throw new InvalidCastException("GCHandle Target could not be cast as List<IntPtr>");
        list.Add(handle);
        return true;
    }
}
}