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。