这是我的第一个 C# 应用程序，完全自学，没有任何软件编程背景。我对撤消/重做进行了一些研究，但找不到任何有用的东西（或易于理解）。因此，我希望有人可以帮助我为我的程序（winforms 应用程序）设计撤消/重做功能。该应用程序由一个主窗体组成，其中将调用后续子窗体以在某些事件（按钮单击等）期间记录用户指定的值。处理完每个事件后，将在缓冲区中绘制一个位图，然后在主窗体的 OnPaint 事件期间将其加载到主窗体内的图片框。每个输入都分离成自定义类对象并添加到单独的 List 和 BindingList 中。List 中包含的对象用于图形（指示坐标等），而 BindingList 中的对象用于在 DataGridView 上显示一些重要值。只是为了给出一个简短的描述，代码看起来像这样：
public partial class MainForm : form
{
public class DataClass_1
{
public double a { get; set; }
public double b { get; set; }
public SubDataClass_1 { get; set; }
}
public class SubDataClass_1
{
public double x { get; set; }
public double y { get; set; }
public string SomeString { get; set; }
public CustomEnum Enum_SubDataClass_1 { get; set; }
}
public class DisplayDataClass
{
public string SomeString { get; set; }
public double e { get; set; }
public double f { get; set; }
}
public enum CustomEnum { Enum1, Enum2, Enum3 };
// Lists that contain objects which hold the necessary values to be drawn and displayed
public List<DataClass_1> List_1 = new List<DataClass_1>();
public List<DataClass_2> List_2 = new List<DataClass_2>(); // Object has similar data types as DataClass_1
public BindingList<DisplayDataClass> DisplayList = new BindingList<DisplayDataClass>();
Bitmap buffer;
public MainForm()
{
InitializeComponent();
dgv.DataSource = DisplayList;
}
private void DrawObject_1()
{
// some drawing codes here
}
private void DrawObject_2()
{
// some drawing codes here
}
protected override void OnPaint(PaintEventArgs e)
{
DrawObject_1();
DrawObject_2();
pictureBox1.Image = buffer;
}
// Event to get input
private void action_button_click(object sender, EventArgs e)
{
ChildForm form = new ChildForm(this);
form.ShowDialog();
Invalidate();
}
}
子表单的代码如下所示：
public partial class ChildForm : form
{
public ChildForm(MainForm MainForm)
{
InitializeComponent();
// Do something
}
private void ok_button_click(object sender, EventArgs e)
{
DataClass_1 Data_1 = new DataClass_1();
DisplayDataClass DisplayData = new DisplayDataClass();
// Parsing, calculations, set values to Data_1 and DisplayData
MainForm.List_1.Add(Data_1);
MainForm.DisplayList.Add(DisplayData);
this.DialogResult = System.Windows.Forms.DialogResult.OK;
this.Close();
}
}
由于所有必要的数据都存储在列表中，并且只有在触发某些事件（主要是按钮单击）后才会更改，因此我尝试使用这些列表来确定运行时应用程序的状态。我实现撤消/重做功能的方法是添加以下代码：
public partial class MainForm : form
{
public class State()
{
public List<DataClass_1> List_1 { get; set; }
public List<DataClass_2> List_2 { get; set; }
public BindingList<DisplayDataClass> DisplayList { get; set; }
// and so on
public State()
{
List_1 = new List<DataClass_1>();
List_2 = new List<DataClass_2>();
DisplayList = new BindingList<DisplayDataClass>();
}
}
State currentState = new State();
Stack<State> undoStack = new Stack<State>();
Stack<State> redoStack = new Stack<State>();
private void MainForm_Shown(object sender, EventArgs e)
{
// Saves original state as first item in undoStack
undoStack.Push(currentState);
}
protected override void OnPaint(PaintEventArgs e)
{
// Update lists from currentState before drawing
List_1 = new List<DataClass_1>(currentState.List_1);
List_2 = new List<DataClass_2>(currentState.List_2);
DisplayList = new BindingList<DisplayDataClass>(currentState.DisplayList);
}
// When undo button is clicked
private void undo_button_Click(object sender, EventArgs e)
{
if (undoStack.Count > 0)
{
redoStack.Push(currentState);
undoStack.Pop();
currentState = undoStack.Last();
Invalidate();
}
}
// When redo button is clicked
private void redo_button_Click(object sender, EventArgs e)
{
// Have not thought about this yet, trying to get undo done first
}
// Events that trigger changes to values held by data objects
private void action_button_Click(object sender, EventArgs e)
{
// Replace the following code with previously stated version
if (form.ShowDialog() == System.Windows.Forms.DialogResult.OK)
{
ChildForm form = new ChildForm(this)
UpdateState();
undoStack.Push(currentState);
Invalidate();
}
}
// To update currentState to current values
private void UpdateState()
{
currentState.List_1 = new List<DataClass_1>(List_1);
currentState.List_2 = new List<DataClass_2>(List_2);
currentState.DisplayList = new BindingList<DisplayDataClass>(DisplayList);
// and so on
}
}
结果： 应用程序未正确执行撤消功能。程序在正常情况下显示正确的输出，但是当触发撤消事件时，无论绘制了多少对象，应用程序都会恢复到初始状态（没有记录数据的状态）。在更改堆栈以检查 undoStack 中的计数数的事件期间，我使用了 System.Diagnostics.Debug.WriteLine() 并且它似乎给出了正确的计数。我猜这些列表需要以不同的方式复制/克隆？还是我在这里做错了什么？谁能指导我？无需考虑性能、可读性、资源管理、未来维护等。