[原创][开源] SunnyUI.Net 开发日志:UIListBox 增加跟随鼠标滑过高亮
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SunnyUI.Net 开发日志:ListBox 增加跟随鼠标滑过高亮
QQ群里,寸木说,ListBox鼠标移动时,当前行需要焦点,我想了想,不难实现啊
不就是在鼠标移动时重绘Item嘛,何况选中的Item已经改了颜色了。
见UIListBox代码:
protected override void OnDrawItem(DrawItemEventArgs e) { base.OnDrawItem(e); BeforeDrawItem?.Invoke(this, Items, e); if (Items.Count == 0) { return; } e.DrawBackground(); if (e.Index < 0 || e.Index >= Items.Count) { return; } StringFormat sStringFormat = new StringFormat(); sStringFormat.LineAlignment = StringAlignment.Center; Color backColor = (e.State & DrawItemState.Selected) == DrawItemState.Selected ? ItemSelectBackColor : BackColor; Color foreColor = (e.State & DrawItemState.Selected) == DrawItemState.Selected ? ItemSelectForeColor : ForeColor; Rectangle rect = new Rectangle(e.Bounds.X, e.Bounds.Y, e.Bounds.Width - 1, e.Bounds.Height - 1); e.Graphics.FillRectangle(BackColor, e.Bounds); e.Graphics.FillRoundRectangle(backColor, rect, 5); e.Graphics.DrawString(Items[e.Index].ToString(), e.Font, foreColor, e.Bounds, sStringFormat); }
看:(e.State & DrawItemState.Selected) == DrawItemState.Selected 选中行状态嘛
看了e.State有e.State == DrawItemState.HotLight,不就是高亮的么,于是开始撸代码,加状态判断
Run
晕。。。没变,这HotLight不起作用,好吧,问度娘。。。
翻山越岭,跋山涉水。。。
找到这篇:https://www.jb51.cc/csharp/101121.html
其中提到:
我在我的WinForms应用程序中使用OwnerDrawFixed作为DrawMode用于自定义ListBox控件.当用户将鼠标悬停在列表框项目上时,我希望重新绘制ListBoxItem的背景(或执行其他操作),即在MouseMove …DrawItemState.HotLight永远不适用于ListBox,所以我想知道如何模拟它,如何解决这个问题.
DrawItemState.HotLight永远不适用于ListBox,是永远。。。怎么这么远。。。
继续往下看:
解决方法
DrawItemState.HotLight仅适用于所有者绘制的菜单,而不适用于列表框.对于ListBox,您必须自己跟踪项目:
public partial class Form1 : Form { private int _MouseIndex = -1; public Form1() { InitializeComponent(); } private void listBox1_DrawItem(object sender,DrawItemEventArgs e) { Brush textBrush = SystemBrushes.WindowText; if (e.Index > -1) { if (e.Index == _MouseIndex) { e.Graphics.FillRectangle(SystemBrushes.HotTrack,e.Bounds); textBrush = SystemBrushes.HighlightText; } else { if ((e.State & DrawItemState.Selected) == DrawItemState.Selected) { e.Graphics.FillRectangle(SystemBrushes.Highlight,e.Bounds); textBrush = SystemBrushes.HighlightText; } else e.Graphics.FillRectangle(SystemBrushes.Window,e.Bounds); } e.Graphics.DrawString(listBox1.Items[e.Index].ToString(),e.Font,textBrush,e.Bounds.Left + 2,e.Bounds.Top); } } private void listBox1_MouseMove(object sender,MouseEventArgs e) { int index = listBox1.IndexFromPoint(e.Location); if (index != _MouseIndex) { _MouseIndex = index; listBox1.Invalidate(); } } private void listBox1_MouseLeave(object sender,EventArgs e) { if (_MouseIndex > -1) { _MouseIndex = -1; listBox1.Invalidate(); } } }
兄弟们,人家这花两年时间解决的,应该有用,继续再找找,又找到一篇洋文的:
https://stackoverflow.com/questions/1316027/listbox-drawitem-hotlight-state-in-the-ownerdraw-mode
It took me only two years to find the answer for you, but here it is:
The DrawItemState.HotLight only applies to owner drawn menus, not the listbox.
For the ListBox, you have to keep track of the item yourself:
看看,也是两年,估计上面中文的从这个翻译过来。
除了这俩,还真没找到。
继续撸代码,果真管用。不过还是有问题,鼠标滑快了,ListBox闪烁的厉害。
分析代码 listBox1.Invalidate(); 这是刷新全部的。鼠标滑过也就和本次选中和上次选中的有关系。
就刷这两个Item就行,有了思路,撸代码三连发:
private int lastIndex = -1; private int mouseIndex = -1; [Browsable(false)] public int MouseIndex { get => mouseIndex; set { if (mouseIndex != value) { if (lastIndex >= 0 && lastIndex != SelectedIndex) { OnDrawItem(new DrawItemEventArgs(this.CreateGraphics(), Font, GetItemRectangle(lastIndex), lastIndex, DrawItemState.Grayed)); } mouseIndex = value; if (mouseIndex >= 0 && mouseIndex != SelectedIndex) { OnDrawItem(new DrawItemEventArgs(this.CreateGraphics(), Font, GetItemRectangle(value), value, DrawItemState.HotLight)); } lastIndex = mouseIndex; } } } protected override void OnMouseMove(MouseEventArgs e) { base.OnMouseMove(e); MouseIndex = IndexFromPoint(e.Location); } protected override void OnMouseLeave(EventArgs e) { base.OnMouseLeave(e); MouseIndex = -1; }
其中 new DrawItemEventArgs(this.CreateGraphics(), Font, GetItemRectangle(value), value, DrawItemState.HotLight)
第一个参数Graphics,也找了一会儿,后来看这篇:
https://www.cnblogs.com/yuanyeguhong/archive/2013/09/20/3330606.html
其实就是Graphics对象的DrawString方法,而参数e中的Graphics是如何来的呢。
我们接着分析DrawItemEventArgs这个类,他既然是对listBox1某一项的属性的打包,
那么我估计其中的Graphics对象就是由listBox1.creatgraphics而来的。
好了,到此我们就可以自定义重绘listbox某项的函数了,可任意调用的哦!
好了,至此,问题都已找到答案,再捋一下思路,把逻辑理顺。撸代码,调试,OK!!!
主要代码如下:
protected override void OnDrawItem(DrawItemEventArgs e) { base.OnDrawItem(e); BeforeDrawItem?.Invoke(this, Items, e); if (Items.Count == 0) { return; } bool otherState = e.State == DrawItemState.Grayed || e.State == DrawItemState.HotLight; if (!otherState) { e.DrawBackground(); } if (e.Index < 0 || e.Index >= Items.Count) { return; } StringFormat sStringFormat = new StringFormat(); sStringFormat.LineAlignment = StringAlignment.Center; bool isSelected = (e.State & DrawItemState.Selected) == DrawItemState.Selected; Color backColor = isSelected ? ItemSelectBackColor : BackColor; Color foreColor = isSelected ? ItemSelectForeColor : ForeColor; Rectangle rect = new Rectangle(e.Bounds.X, e.Bounds.Y, e.Bounds.Width - 1, e.Bounds.Height - 1); if (!otherState) { e.Graphics.FillRectangle(BackColor, e.Bounds); e.Graphics.FillRoundRectangle(backColor, rect, 5); e.Graphics.DrawString(Items[e.Index].ToString(), e.Font, foreColor, e.Bounds, sStringFormat); } else { if (e.State == DrawItemState.Grayed) { backColor = BackColor; foreColor = ForeColor; } if (e.State == DrawItemState.HotLight) { backColor = HoverColor; foreColor = ForeColor; } e.Graphics.FillRectangle(BackColor, e.Bounds); e.Graphics.FillRoundRectangle(backColor, rect, 5); e.Graphics.DrawString(Items[e.Index].ToString(), e.Font, foreColor, e.Bounds, sStringFormat); } AfterDrawItem?.Invoke(this, Items, e); }
看,DrawItemState.HotLight咱也给实现了,DrawItemState.Grayed 我是随便选的状态,区别于其他。
想看全部代码,看我的开源项目吧,https://gitee.com/yhuse/SunnyUI ,哎,客官别走嘛,点个Star先。