OK，你的问题其实是如何隐藏一个ListView Column？. 网上很多人都问过这个问题。我试过搜索很多，但找不到任何东西。我最终得到了唯一的解决方案：将列宽设置为零。这将在这里使用一些技巧：
//This will try hiding the column at index 1
listView1.Columns[1].Width = 0;
//ColumnWidthChanging event handler of your ListView
private void listView1_ColumnWidthChanging(object sender, ColumnWidthChangingEventArgs e){
if(e.ColumnIndex == 1){
e.Cancel = true;
e.NewWidth = 0;
}
}
它工作得几乎完美。但是，当用户将鼠标移到pipe隐藏列的位置时，会出现一个Cursor指示符来通知用户，例如There is a Zero-width column here，只需按住鼠标并拖动即可调整其大小。当然，用户不能从零调整它的大小，因为我们Cancel做了它NewWidth = 0（就像上面的代码一样）。但是Cursor通知这样的操作有点讨厌，这里是演示问题的屏幕截图：
解决这个问题并不容易。至少我是这样的感觉。我想到了这个似乎可以正常工作的解决方案。这个想法是我们必须检测鼠标是否在隐藏列的管道附近，我们必须设置Cursor = Cursors.Arrow. 这是我认为对你很有用的整个课程：
public class CustomListView : ListView
{
[DllImport("user32")]
private static extern bool EnumChildWindows(IntPtr parentHwnd, EnumChildProc proc, object lParam);
delegate bool EnumChildProc(IntPtr childHwnd, object lParam);
public CustomListView()
{
VisibleChanged += (s, e) =>
{
if (Visible && headerHandle == IntPtr.Zero&&!DesignMode)
{
EnumChildWindows(Handle, EnumChild, null);
headerProc = new HeaderProc(this);
headerProc.AssignHandle(headerHandle);
}
};
columnPipeLefts[0] = 0;
}
//Save the Handle to the Column Headers, a ListView has only child Window which is used to render Column headers
IntPtr headerHandle;
//This is used use to hook into the message loop of the Column Headers
HeaderProc headerProc;
private bool EnumChild(IntPtr childHwnd, object lParam)
{
headerHandle = childHwnd;
return true;
}
//Updated code
protected override void WndProc(ref Message m)
{
if (m.Msg == 0x101e&&hiddenColumnIndices.Contains(m.WParam.ToInt32()))//WM_SETCOLUMNWIDTH = 0x101e
{
if(m.LParam.ToInt32() > 0) hiddenColumnWidths[m.WParam.ToInt32()] = m.LParam.ToInt32();
return;//Discard the message changing hidden column width so that it won't be shown again.
}
base.WndProc(ref m);
}
//Save the column indices which are hidden
List<int> hiddenColumnIndices = new List<int>();
//Save the width of hidden columns
Dictionary<int, int> hiddenColumnWidths = new Dictionary<int, int>();
//Save the Left (X-Position) of the Pipes which separate Column Headers.
Dictionary<int, int> columnPipeLefts = new Dictionary<int, int>();
protected override void OnColumnWidthChanging(ColumnWidthChangingEventArgs e)
{
if (hiddenColumnIndices.Contains(e.ColumnIndex))
{
e.Cancel = true;
e.NewWidth = 0;
}
base.OnColumnWidthChanging(e);
}
//We need to update columnPipeLefts whenever the width of any column changes
protected override void OnColumnWidthChanged(ColumnWidthChangedEventArgs e)
{
base.OnColumnWidthChanged(e);
UpdateColumnPipeLefts(Columns[e.ColumnIndex].DisplayIndex + 1);
}
int index = -1;
protected override void OnColumnReordered(ColumnReorderedEventArgs e)
{
int i = Math.Min(e.NewDisplayIndex, e.OldDisplayIndex);
index = index != -1 ? Math.Min(i + 1, index) : i + 1;
base.OnColumnReordered(e);
}
//This is used to update the columnPipeLefts every reordering columns or resizing columns.
private void UpdateColumnPipeLefts(int fromIndex)
{
int w = fromIndex > 0 ? columnPipeLefts[fromIndex - 1] : 0;
for (int i = fromIndex; i < Columns.Count; i++)
{
w += i > 0 ? Columns.OfType<ColumnHeader>().Where(k=>k.DisplayIndex == i - 1).Single().Width : 0;
columnPipeLefts[i] = w;
}
}
//This is used to hide a column with ColumnHeader passed in
public void HideColumn(ColumnHeader col)
{
if (!hiddenColumnIndices.Contains(col.Index))
{
hiddenColumnWidths[col.Index] = col.Width;//Save the current width to restore later
col.Width = 0;//Hide the column
hiddenColumnIndices.Add(col.Index);
}
}
//This is used to hide a column with column index passed in
public void HideColumn(int columnIndex)
{
if (columnIndex < 0 || columnIndex >= Columns.Count) return;
if (!hiddenColumnIndices.Contains(columnIndex))
{
hiddenColumnWidths[columnIndex] = Columns[columnIndex].Width;//Save the current width to restore later
Columns[columnIndex].Width = 0;//Hide the column
hiddenColumnIndices.Add(columnIndex);
}
}
//This is used to show a column with ColumnHeader passed in
public void ShowColumn(ColumnHeader col)
{
hiddenColumnIndices.Remove(col.Index);
if(hiddenColumnWidths.ContainsKey(col.Index))
col.Width = hiddenColumnWidths[col.Index];//Restore the Width to show the column
hiddenColumnWidths.Remove(col.Index);
}
//This is used to show a column with column index passed in
public void ShowColumn(int columnIndex)
{
if (columnIndex < 0 || columnIndex >= Columns.Count) return;
hiddenColumnIndices.Remove(columnIndex);
if(hiddenColumnWidths.ContainsKey(columnIndex))
Columns[columnIndex].Width = hiddenColumnWidths[columnIndex];//Restore the Width to show the column
hiddenColumnWidths.Remove(columnIndex);
}
//The helper class allows us to hook into the message loop of the Column Headers
private class HeaderProc : NativeWindow
{
[DllImport("user32")]
private static extern int SetCursor(IntPtr hCursor);
public HeaderProc(CustomListView listView)
{
this.listView = listView;
}
bool mouseDown;
CustomListView listView;
protected override void WndProc(ref Message m)
{
if (m.Msg == 0x200 && listView!=null && !mouseDown)
{
int x = (m.LParam.ToInt32() << 16) >> 16;
if (IsSpottedOnAnyHiddenColumnPipe(x)) return;
}
if (m.Msg == 0x201) {
mouseDown = true;
int x = (m.LParam.ToInt32() << 16) >> 16;
IsSpottedOnAnyHiddenColumnPipe(x);
}
if (m.Msg == 0x202) mouseDown = false;
if (m.Msg == 0xf && listView.index != -1 && MouseButtons == MouseButtons.None) { //WM_PAINT = 0xf
listView.UpdateColumnPipeLefts(listView.index);
listView.index = -1;
};
base.WndProc(ref m);
}
private bool IsSpottedOnAnyHiddenColumnPipe(int x)
{
foreach (int i in listView.hiddenColumnIndices.Select(j=>listView.Columns[j].DisplayIndex))
{
if (x > listView.columnPipeLefts[i] - 1 && x < listView.columnPipeLefts[i] + 15)
{
SetCursor(Cursors.Arrow.Handle);
return true;
}
}
return false;
}
}
}