c 设计带图标和自定义颜色的listbox（C designs ListBox with icons and custom colors）

c 带图标和自定义颜色的listbox（C designs ListBox with icons and custom colors） c#设计带图标和自定义颜色的listbox(C# designs ListBox with icons and custom colors) C# designs ListBox with icons and custom colors The C# design, with icons and custom colors, is the key word for ListBox, C#, ListBox, and color, In a peer-to-peer file transfer project, I need to display the real-time information of file transfer: transfer file list and the current file transfer, then I think of ListBox, but I used ListBox, I found it could not change the text color to control, so I want to expand out. ListBox control ------ListBoxEx. My goal is to add icons to space and to change the text color of the control at any time. The class is derived from the ListBox Public class ListBoxEx: ListBox {... } For ease of operation, I designed a special class ListBoxEx for each item of ListBoxExItem Public, class, ListBoxExItem {... } To keep my control in line with the standard manipulation of WinForm's standard controls, I redesigned two collection classes: Public class ListBoxExItemCollection: IList, ICollection, IEnumerator {} / / this class compared to the standard ListBox ObjectCollection in this class as a Items attribute in ListBoxEx type Public, class, SelectedListBoxExItemCollection:: IList, ICollection, IEnumerator{} / / this class compared to the standard ListBox SelectedObjectCollection in this class as a SelectedItems attribute in ListBoxEx type See below the implementation of the two collection class: The implementation of ListBoxExItemCollection: in order to achieve the set (Items) operation can be reflected to the ListBoxEx control so that such is only for ListBox Items (type ObjectCollection) made a layer of packaging, is that all the Items property in the ListBox as long as the parameters of type object are converted to ListBoxExItem, for example: Public void Remove (ListBoxExItem item) { This._Items.Remove (item); //_Items is the ObjectCollection type } Public, void, Insert (int, index, ListBoxExItem, item) { This._Items.Insert (index, item); } Public int Add (ListBoxExItem item) { Return this._Items.Add (item); } As you can see, there is a constructor in ListBoxExItemCollection to pass the Items object in ListBox Private ObjectCollection _Items; Public ListBoxExItemCollection (ObjectCollection baseItems) { This._Items = baseItems; } The implementation of the SelectedListBoxExItemCollection class is the same way, just wrapping the SelectedObjectCollection. After the collection is implemented, let's look at the implementation of ListBoxExItem: To enable it to support icons and multiple colors, add the following members Private int _ImageIndex; Public int ImageIndex { Get {return this._ImageIndex} Set {this._ImageIndex = value} } Private Color _ForeColor; Public Color ForeColor { Get{return this._ForeColor;} Set { This._ForeColor = value; This.Parent.Invalidate (); } } Of course: Private string _Text; Public string Text { Get {return this._Text} Set {this._Text = value} } In order for the control to display the text of the item correctly, you must override the ToString () method 公共tostring()重写字符串 { 这_text返回; } 再看listboxex的实现: 为了使控件能够自我绘制，所以:DrawMode = drawmode.ownerdrawfixed; 为了覆盖基类的项目等相关属性添加 私人listboxexitemcollection _items;/ /在构造函数中创建 同时还需要重写属性项目: 新公共listboxexitemcollection项目 { 得到 { 这_items返回; } } 新市民ListBoxExItem SelectedItem /强制转换为listboxexitem { 得到的回报是listboxexitem base.selecteditem {;} 集合{ base.selecteditem =值;} } 新市民SelectedListBoxExItemCollection SelectedItems /重新包 装selecteditems { 得到 { 返回新的selectedlistboxexitemcollection(基地。selecteditems); } } 为了支持图标，添加一个图像列ImageList 私人的ImageList的ImageList; 市民ImageList ImageList { 得到的回报this.imagelist {;} 设置 { this.imagelist =价值; 这invalidate();/ /图像列表改变后马上更新控件。 } } 而此控件的核心却在一个方法OnDrawItem，这个方法每当控件的项需要重绘时就被调用 OnDrawItem(system.windows.forms.drawitemeventargs PE保护覆盖无效) { drawbackground();/ /画背景PE。 drawfocusrectangle();/ /画边框PE。 矩形边界; /检查索引是否有效。 如果(pe.index > = 0和PE。指数,基地。项目。计数) { listboxexitem项目=本吧。 这篇C #设计带图标和自定义颜色的ListBox的关键词是C #，列表框，颜色，EMS [体育] / /取得需要绘制项的引用。指数; int IOFFSET = 0; /如果图像列表存在并设置了图像索引，则绘制图像。 如果(this.imagelist～= null) { 如果(item.imageindex > - 1和item.imageindex <这个ImageList。图像。计数) { 这个ImageList。画(pe.graphics，界限。左边界。顶部边界。高度、界限。高度、项目。ImageIndex);/ /绘制图标 } IOFFSET + =界限。高度;/ / this.imagelist.imagesize.width; } //绘制项目文本 体育。图形。束带(item.text，PE。字体，新的SolidBrush(项目。 前景色)，bounds.left + IOFFSET界限。顶部);/ /根据项的颜色绘制文本 } OnDrawItem(PE)的基础; } } 到此为止，listboxex以完整的实现，并且支持可视化设计。