当单击发生在子项之外时调用 ListViews base.WndProc 时的 ArgOutOfRangeEx，C# 10.0

Question

我在 OwnerDrawn 列表视图中调用 base.WndProc 时收到 ArgumentOutOfRangeException。

在任何 ListViewItem 的最后一个子项的右侧（空白区域）执行单击后，会发生异常。

列表视图列宽度以编程方式设置为填充整个列表视图，但是有时未按预期接收数据，导致一些额外的空间，这是通常不会发生的边缘情况。

异常时要处理的消息是WM_LBUTTONDOWN（0x0201）或WM_RBUTTONDOWN（0x0204）。

用于绘制 LV 子项的所有数据都来自 LVI 标签引用的类，我在任何时候都不会尝试读取子项，也不会将数据写入任何子项。 下面是最小的可重现代码，采用 C# (10.0)，使用 .NET 6.0 显示异常。

我试图简单地排除 WM_LBUTTONDOWN 的处理。这确实消除了异常，但它也阻止了左键单击事件到达所需的 MouseUp。 （也适用于右键单击）

虽然我正在努力修复收到错误数据或没有数据后列大小调整中的错误，但我想检查是否存在此可能的异常，并在异常发生之前从该方法返回。

数据类

namespace testCase;
class myClass
{
    public string s1 = "subitem1";
    public string s2 = "subitem2";
}

表单代码

namespace testCase;
public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
        ListViewExWatch lv = new();
        Controls.Add(lv);
        lv.MouseUp += Lv_MouseUp;
        lv.Top = 0;
        lv.Left = 0;
        lv.Width = ClientSize.Width;
        lv.Height = ClientSize.Height;
        lv.OwnerDraw = true;
        lv.BackColor = Color.AntiqueWhite;
        lv.Columns.Add("Row", 50);
        lv.Columns.Add("sub1", 50);
        lv.Columns.Add("sub2", 50);

        for(int i = 0; i < 10; i++)
        {
            ListViewItem lvi = new(){ Text = "Row " + i, Tag = new myClass() };
            lvi.SubItems.Add("");
            lvi.SubItems.Add("");
            lv.Items.Add(lvi);
        }
                
    }

    private void Lv_MouseUp(object? sender, MouseEventArgs e)
    {
        if (e.Button == MouseButtons.Left)
        {
            MessageBox.Show("Left click - doing action A");
        }
        if (e.Button == MouseButtons.Right)
        {
            MessageBox.Show("Right click - Creating context menu");
        }
    }
}

自定义 ListView 覆盖

using System.Runtime.InteropServices;
namespace testCase;
public class ListViewExWatch : ListView
{
    #region Windows API
    [StructLayout(LayoutKind.Sequential)]
    struct DRAWITEMSTRUCT
    {
        public int    ctlType;
        public int    ctlID;
        public int    itemID;
        public int    itemAction;
        public int    itemState;
        public IntPtr hWndItem;
        public IntPtr hDC;
        public int    rcLeft;
        public int    rcTop;
        public int    rcRight;
        public int    rcBottom;
        public IntPtr itemData;
    }

    const int LVS_OWNERDRAWFIXED = 0x0400;
    const int WM_SHOWWINDOW      = 0x0018;
    const int WM_DRAWITEM        = 0x002B;
    const int WM_MEASUREITEM     = 0x002C;
    const int WM_REFLECT         = 0x2000;
    const int WM_LBUTTONDOWN     = 0x0201;
    #endregion

    public ListViewExWatch()
    {
        SetStyle(ControlStyles.OptimizedDoubleBuffer | ControlStyles.AllPaintingInWmPaint, true);
    }

    protected override CreateParams CreateParams
    {
        get
        {
            CreateParams k_Params = base.CreateParams;
            k_Params.Style |= LVS_OWNERDRAWFIXED;
            return k_Params;
        }
    }


    protected override void WndProc(ref Message k_Msg)
    {
        //if (k_Msg.Msg == WM_LBUTTONDOWN) return;
        base.WndProc(ref k_Msg); // Exception: System.ArgumentOutOfRangeException: 'InvalidArgument=Value of '-1' is not valid for 'index'. 
        // Only occurs when clicking to the right of the last subItem

        switch (k_Msg.Msg)
        {
            case WM_SHOWWINDOW:
                View = View.Details;
                OwnerDraw = false;
                break;
            case WM_REFLECT + WM_MEASUREITEM:
                Marshal.WriteInt32(k_Msg.LParam + 4 * sizeof(int), 14);
                k_Msg.Result = (IntPtr)1;
                break;
            case WM_REFLECT + WM_DRAWITEM:
                {
                    object? lParam = k_Msg.GetLParam(typeof(DRAWITEMSTRUCT));
                    if (lParam is null) throw new Exception("lParam shouldn't be null");
                    DRAWITEMSTRUCT k_Draw = (DRAWITEMSTRUCT)lParam;
                    using Graphics gfx = Graphics.FromHdc(k_Draw.hDC);

                    ListViewItem lvi = Items[k_Draw.itemID];
                    myClass wi = (myClass)lvi.Tag;

                    TextRenderer.DrawText(gfx, lvi.Text, Font, lvi.SubItems[0].Bounds, Color.Black, TextFormatFlags.Left);
                    TextRenderer.DrawText(gfx, wi.s1, Font, lvi.SubItems[1].Bounds, Color.Black, TextFormatFlags.Left);
                    TextRenderer.DrawText(gfx, wi.s2, Font, lvi.SubItems[2].Bounds, Color.Black, TextFormatFlags.Left);
                    break;
                }
        }
    }
}

错误消息

System.ArgumentOutOfRangeException
  HResult=0x80131502
  Message=InvalidArgument=Value of '-1' is not valid for 'index'. Arg_ParamName_Name
ArgumentOutOfRange_ActualValue
  Source=System.Windows.Forms
  StackTrace:
   at System.Windows.Forms.ListViewItem.ListViewSubItemCollection.get_Item(Int32 index)
   at System.Windows.Forms.ListView.HitTest(Int32 x, Int32 y)
   at System.Windows.Forms.ListView.ListViewAccessibleObject.HitTest(Int32 x, Int32 y)
   at System.Windows.Forms.ListView.WmMouseDown(Message& m, MouseButtons button, Int32 clicks)
   at System.Windows.Forms.ListView.WndProc(Message& m)
   at testCase.ListViewExWatch.WndProc(Message& k_Msg) in C:\Users\XXXX\source\repos\testCase\ListViewExWatch.cs:line 50
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, WM msg, IntPtr wparam, IntPtr lparam)

从错误中可以明显看出，基本列表视图代码试图获取不存在的子项，因为单击不在子项上，因此 -1 表示索引内错误信息。

发生异常时，k_Msg 中不存在包含索引 (-1) 的成员，因此我无法检查并简单地返回。

我可以将对 base.WndProc 的调用包含在 try catch 中，因为它是一种边缘情况。我一直有这样的心态：检查可能的异常并尽可能阻止它们，而不是捕获它们。但这一件却把我难住了。 我在这方面是不是太迂腐了？

我很可能在这里遗漏了一些基本的东西，各位好心人能否指出我正确的方向？

Answer 1

我已经实现了以下代码来仅捕获这个特定的异常，并且仍然允许任何其他异常根据需要冒泡。

try
{
    base.WndProc(ref k_Msg); // This throws a ArgOutOfRangeEx when a click is performed to the right of any subitem (empty space)
}
catch (ArgumentOutOfRangeException ex) when (ex.ParamName == "index" && (int?)ex.ActualValue == -1 && ex.TargetSite?.DeclaringType?.Name == "ListViewSubItemCollection")
{
    Program.Log(LogLevel.Normal, "ListViewExWatch.WndProc()", "ArgumentOutOfRangeException: A click has been perfored outside of a valid subitem. This has been handled and indicates column witdth calcs were wrong.");
    return;
}

然而，通过进一步的研究，我设法专门解决了这个问题

https ://learn.microsoft.com/en-us/windows/win32/inputdev/wm-lbuttondown

l参数

低位字指定光标的 x 坐标...
高位字指定光标的 y 坐标...

我最终在处理消息之前修改了lParam。通过将 x 坐标移动到最后一个子项目内部，可以避免异常，并且可以正常处理点击。

protected override void WndProc(ref Message k_Msg)
{
    if (k_Msg.Msg == WM_LBUTTONDOWN || k_Msg.Msg == WM_RBUTTONDOWN)
    {
        // Get the x position of the end of the last subitem
        int width = -1;
        foreach (ColumnHeader col in Columns) width += col.Width;

        // Where did the click occur?
        int x_click = SignedLOWord(k_Msg.LParam);
        int y_click = SignedHIWord(k_Msg.LParam);

        // If the click is to the right of the last subitem, set the x-coordinate to inside the last subitem.
        if (x_click > width) k_Msg.LParam = MakeLparam(width, y_click);
    }

    base.WndProc(ref k_Msg);
    ...

有趣的是，Lv_MouseUp 处理程序中仍然报告了正确的 x 和 y 坐标。对于其他处理程序（例如 MouseDown ），情况可能并非如此，它显然已被修改，因为我不使用它们，所以没有出现问题

这里是上面使用的辅助函数（来自 referencesource.microsoft.com)

public static IntPtr MakeLparam(int low, int high)
{
    return (IntPtr)((high << 16) | (low & 0xffff));
}
public static int SignedHIWord(IntPtr n)
{
    return SignedHIWord(unchecked((int)(long)n));
}
public static int SignedLOWord(IntPtr n)
{
    return SignedLOWord(unchecked((int)(long)n));
}
public static int SignedHIWord(int n)
{
    return (short)((n >> 16) & 0xffff);
}
public static int SignedLOWord(int n)
{
    return (short)(n & 0xFFFF);
}