C#自定义DataGridViewColumn显示TreeView

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） 

/// <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。