winform 禁用最大化最小化和关闭按钮

不能使用最大化窗口：MaximuzeBox 设为False
不能使用最小化窗口：MinimizeBox 设为False
不能使用红叉关闭
using System.Runtime.InteropServices;

[DllImport("user32.dll")]
internal static extern IntPtr GetSystemMenu(IntPtr hwnd, bool bRevert);

[DllImport("user32.dll")]
internal static extern int GetMenuItemCount(IntPtr hMenu);

[DllImport("user32.dll")]
internal static extern int RemoveMenu(IntPtr hMenu, int uPosition, int uFlags);

/// <summary>
/// 窗体的关闭按钮失效
/// </summary>
protected void CloseButtonEnable()
{
// 默认窗口去除关闭按钮
const int MF_BYPOSITION = 0x00000400;

IntPtr hWindow = this.Handle;
IntPtr hMenu = GetSystemMenu(hWindow, false);
int count = GetMenuItemCount(hMenu);
RemoveMenu(hMenu, count - 1, MF_BYPOSITION);
RemoveMenu(hMenu, count - 2, MF_BYPOSITION);
}

private void confirm_Load(object sender, EventArgs e)
{
CloseButtonEnable();

}

其他

禁止combobox输入方法：将DropDownStyle 设为DropDownList
禁止Form窗口调整大小方法：FormBorderStyle 设为FixedSingle