C#自定义DataGridViewColumn显示TreeView

内容摘要
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


　TreeVi
文章正文

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）。

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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：

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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：

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/// <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：

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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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