我们可以自定义datagridview的datagridviewcolumn来实现自定义的列，下面介绍一下如何通过扩展datagridviewcolumn来实现一个treeviewcolumn
1.treeviewcolumn类
treeviewcolumn继承自datagridviewcolumn，为了动态给treeviewcolumn传入一个treeview，这里暴露出一个公共属性_root，可以绑定一个初始化的treeview. 另外需要重写datagridcell类型的celltemplate，这里返还一个treeviewcell（需要自定义）
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/// <summary>
/// host treeview in datagridview cell
/// </summary>
public class treeviewcolumn : datagridviewcolumn
{
public treeviewcolumn()
: base(new treeviewcell())
{
}
[description("set treeview root in datagridview cell"), category("treeview")]
public treeview _root
{
get{return roots.tree;}
set{roots.tree=value;}
}
public override datagridviewcell celltemplate
{
get
{
return base.celltemplate;
}
set
{
// ensure that the cell used for the template is a treeviewcell.
if (value != null &&
!value.gettype().isassignablefrom(typeof(treeviewcell)))
{
throw new invalidcastexception("must be a treeviewcell");
}
base.celltemplate = value;
}
}
}
2.treeviewcell类
上面treeviewcolumn重写了celltemplate，返回的就是自定义的treeviewcell，这里就是具体实现其逻辑。一般来说选择树控件的节点后，返回的是一个文本信息，是文本类型，可以继承datagridviewtextboxcell,并重写initializeeditingcontrol来进行自定义的datagridview.editingcontrol （编辑控件）。
public class treeviewcell : datagridviewtextboxcell
{
public treeviewcell()
: base()
{
//初始设置
}
public override void initializeeditingcontrol(int rowindex, object
initialformattedvalue, datagridviewcellstyle datagridviewcellstyle)
{
// set the value of the editing control to the current cell value.
base.initializeeditingcontrol(rowindex, initialformattedvalue,
datagridviewcellstyle);
treevieweditingcontrol ctl =
datagridview.editingcontrol as treevieweditingcontrol;
// use the default row value when value property is null.
if (this.value == null)
{
ctl.selectednode =new treenode( this.defaultnewrowvalue.tostring());
}
else
{
ctl.selectednode = new treenode(this.value.tostring());
}
}
public override type edittype
{
get
{
// return the type of the editing control that calendarcell uses.
return typeof(treevieweditingcontrol);
}
}
public override type valuetype
{
get
{
// return the type of the value that calendarcell contains.
return typeof(string);
}
}
public override object defaultnewrowvalue
{
get
{
// use the current date and time as the default value.
return "";
}
}
}
3.treevieweditingcontrol类
treevieweditingcontrol为编辑控件，当用户编辑treeviewcell时，显示的为树编辑控件，需要继承treeview，同时实现idatagridvieweditingcontrol接口，实现以下方法：
public class treevieweditingcontrol : treeview, idatagridvieweditingcontrol
{
datagridview datagridview;
private bool valuechanged = false;
int rowindex;
public treevieweditingcontrol()
{
try
{
//必须加roots.tree.nodes[].clone() 否则报错 不能在多处增添或插入项，必须首先将其从当前位置移除或将其克隆
this.nodes.add(roots.tree.nodes[].clone() as treenode);
this.selectednode = this.nodes[];
}
catch (exception ex)
{
messagebox.show(ex.message);
}
}
// implements the idatagridvieweditingcontrol.editingcontrolformattedvalue
// property.
public object editingcontrolformattedvalue
{
get
{
return this.selectednode.text;
}
set
{
if (value is string)
{
try
{
// this will throw an exception of the string is
// null, empty, or not in the format of a date.
this.selectednode = new treenode((string)value);
}
catch
{
// in the case of an exception, just use the
// default value so we're not left with a null
// value.
this.selectednode = new treenode("");
}
}
}
}
// implements the
// idatagridvieweditingcontrol.geteditingcontrolformattedvalue method.
public object geteditingcontrolformattedvalue(
datagridviewdataerrorcontexts context)
{
return editingcontrolformattedvalue;
}
// implements the
// idatagridvieweditingcontrol.applycellstyletoeditingcontrol method.
public void applycellstyletoeditingcontrol(
datagridviewcellstyle datagridviewcellstyle)
{
this.font = datagridviewcellstyle.font;
this.forecolor = datagridviewcellstyle.forecolor;
this.backcolor = datagridviewcellstyle.backcolor;
}
// implements the idatagridvieweditingcontrol.editingcontrolrowindex
// property.
public int editingcontrolrowindex
{
get
{
return rowindex;
}
set
{
rowindex = value;
}
}
// implements the idatagridvieweditingcontrol.editingcontrolwantsinputkey
// method.
public bool editingcontrolwantsinputkey(
keys key, bool datagridviewwantsinputkey)
{
// let the treeviewpicker handle the keys listed.
switch (key & keys.keycode)
{
case keys.left:
case keys.up:
case keys.down:
case keys.right:
case keys.home:
case keys.end:
case keys.pagedown:
case keys.pageup:
return true;
default:
return !datagridviewwantsinputkey;
}
}
// implements the idatagridvieweditingcontrol.prepareeditingcontrolforedit
// method.
public void prepareeditingcontrolforedit(bool selectall)
{
// no preparation needs to be done.
}
// implements the idatagridvieweditingcontrol
// .repositioneditingcontrolonvaluechange property.
public bool repositioneditingcontrolonvaluechange
{
get
{
return false;
}
}
// implements the idatagridvieweditingcontrol
// .editingcontroldatagridview property.
public datagridview editingcontroldatagridview
{
get
{
return datagridview;
}
set
{
datagridview = value;
}
}
// implements the idatagridvieweditingcontrol
// .editingcontrolvaluechanged property.
public bool editingcontrolvaluechanged
{
get
{
return valuechanged;
}
set
{
valuechanged = value;
}
}
// implements the idatagridvieweditingcontrol
// .editingpanelcursor property.
public cursor editingpanelcursor
{
get
{
return base.cursor;
}
}
protected override void onafterexpand(treevieweventargs e)
{
base.onafterexpand(e);
this.datagridview.columns[this.datagridview.currentcell.columnindex].width = this.width+;
this.datagridview.rows[this.datagridview.currentcell.rowindex].height = this.height+;
}
protected override void onafterselect(treevieweventargs e)
{
// notify the datagridview that the contents of the cell
// have changed.
valuechanged = true;
this.editingcontroldatagridview.notifycurrentcelldirty(true);
base.onafterselect(e);
}
}
为了在不同类之间传递参数，定义一个全局静态类：
/// <summary>
/// 静态类的静态属性，用于在不同class间传递参数
/// </summary>
public static class roots
{
//从前台绑定树
public static treeview tree = null;
}
完整代码为：
using system;
using system.collections.generic;
using system.linq;
using system.text;
using system.windows.forms;
using system.componentmodel;
namespace host_controls_in_windows_forms_datagridview_cells
{
/// <summary>
/// 静态类的静态属性，用于在不同class间传递参数
/// </summary>
public static class roots
{
//从前台绑定树
public static treeview tree = null;
}
/// <summary>
/// host treeview in datagridview cell
/// </summary>
public class treeviewcolumn : datagridviewcolumn
{
public treeviewcolumn()
: base(new treeviewcell())
{
}
[description("set treeview root in datagridview cell"), category("treeview")]
public treeview _root
{
get{return roots.tree;}
set{roots.tree=value;}
}
public override datagridviewcell celltemplate
{
get
{
return base.celltemplate;
}
set
{
// ensure that the cell used for the template is a treeviewcell.
if (value != null &&
!value.gettype().isassignablefrom(typeof(treeviewcell)))
{
throw new invalidcastexception("must be a treeviewcell");
}
base.celltemplate = value;
}
}
}
//----------------------------------------------------------------------
public class treeviewcell : datagridviewtextboxcell
{
public treeviewcell()
: base()
{
//初始设置
}
public override void initializeeditingcontrol(int rowindex, object
initialformattedvalue, datagridviewcellstyle datagridviewcellstyle)
{
// set the value of the editing control to the current cell value.
base.initializeeditingcontrol(rowindex, initialformattedvalue,
datagridviewcellstyle);
treevieweditingcontrol ctl =
datagridview.editingcontrol as treevieweditingcontrol;
// use the default row value when value property is null.
if (this.value == null)
{
ctl.selectednode =new treenode( this.defaultnewrowvalue.tostring());
}
else
{
ctl.selectednode = new treenode(this.value.tostring());
}
}
public override type edittype
{
get
{
// return the type of the editing control that calendarcell uses.
return typeof(treevieweditingcontrol);
}
}
public override type valuetype
{
get
{
// return the type of the value that calendarcell contains.
return typeof(string);
}
}
public override object defaultnewrowvalue
{
get
{
// use the current date and time as the default value.
return "";
}
}
}
//-----------------------------------------------------------------
public class treevieweditingcontrol : treeview, idatagridvieweditingcontrol
{
datagridview datagridview;
private bool valuechanged = false;
int rowindex;
public treevieweditingcontrol()
{
try
{
//必须加roots.tree.nodes[].clone() 否则报错 不能在多处增添或插入项，必须首先将其从当前位置移除或将其克隆
this.nodes.add(roots.tree.nodes[].clone() as treenode);
this.selectednode = this.nodes[];
}
catch (exception ex)
{
messagebox.show(ex.message);
}
}
// implements the idatagridvieweditingcontrol.editingcontrolformattedvalue
// property.
public object editingcontrolformattedvalue
{
get
{
return this.selectednode.text;
}
set
{
if (value is string)
{
try
{
// this will throw an exception of the string is
// null, empty, or not in the format of a date.
this.selectednode = new treenode((string)value);
}
catch
{
// in the case of an exception, just use the
// default value so we're not left with a null
// value.
this.selectednode = new treenode("");
}
}
}
}
// implements the
// idatagridvieweditingcontrol.geteditingcontrolformattedvalue method.
public object geteditingcontrolformattedvalue(
datagridviewdataerrorcontexts context)
{
return editingcontrolformattedvalue;
}
// implements the
// idatagridvieweditingcontrol.applycellstyletoeditingcontrol method.
public void applycellstyletoeditingcontrol(
datagridviewcellstyle datagridviewcellstyle)
{
this.font = datagridviewcellstyle.font;
this.forecolor = datagridviewcellstyle.forecolor;
this.backcolor = datagridviewcellstyle.backcolor;
}
// implements the idatagridvieweditingcontrol.editingcontrolrowindex
// property.
public int editingcontrolrowindex
{
get
{
return rowindex;
}
set
{
rowindex = value;
}
}
// implements the idatagridvieweditingcontrol.editingcontrolwantsinputkey
// method.
public bool editingcontrolwantsinputkey(
keys key, bool datagridviewwantsinputkey)
{
// let the treeviewpicker handle the keys listed.
switch (key & keys.keycode)
{
case keys.left:
case keys.up:
case keys.down:
case keys.right:
case keys.home:
case keys.end:
case keys.pagedown:
case keys.pageup:
return true;
default:
return !datagridviewwantsinputkey;
}
}
// implements the idatagridvieweditingcontrol.prepareeditingcontrolforedit
// method.
public void prepareeditingcontrolforedit(bool selectall)
{
// no preparation needs to be done.
}
// implements the idatagridvieweditingcontrol
// .repositioneditingcontrolonvaluechange property.
public bool repositioneditingcontrolonvaluechange
{
get
{
return false;
}
}
// implements the idatagridvieweditingcontrol
// .editingcontroldatagridview property.
public datagridview editingcontroldatagridview
{
get
{
return datagridview;
}
set
{
datagridview = value;
}
}
// implements the idatagridvieweditingcontrol
// .editingcontrolvaluechanged property.
public bool editingcontrolvaluechanged
{
get
{
return valuechanged;
}
set
{
valuechanged = value;
}
}
// implements the idatagridvieweditingcontrol
// .editingpanelcursor property.
public cursor editingpanelcursor
{
get
{
return base.cursor;
}
}
protected override void onafterexpand(treevieweventargs e)
{
base.onafterexpand(e);
this.datagridview.columns[this.datagridview.currentcell.columnindex].width = this.width+;
this.datagridview.rows[this.datagridview.currentcell.rowindex].height = this.height+;
}
protected override void onafterselect(treevieweventargs e)
{
// notify the datagridview that the contents of the cell
// have changed.
valuechanged = true;
this.editingcontroldatagridview.notifycurrentcelldirty(true);
base.onafterselect(e);
}
}
}
当编辑无误后，可以在添加列的时候看到treeviewcolumn类型。此类型暴露出一个_root属性，可以绑定外部的一个带数据的treeview。
运行代码，单击单元格，进入编辑状态，可以看到如下界面：
以上内容是小编给大家介绍的c#自定义datagridviewcolumn显示treeview 的全部叙述，希望大家喜欢。
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