我們可以自定義DataGridView的DataGridViewColumn來實現(xiàn)自定義的列，下面介紹一下如何通過擴(kuò)展DataGridViewColumn來實現(xiàn)一個TreeViewColumn
1.TreeViewColumn類
TreeViewColumn繼承自DataGridViewColumn，為了動態(tài)給TreeViewColumn傳入一個TreeView，這里暴露出一個公共屬性_root，可以綁定一個初始化的TreeView. 另外需要重寫DataGridCell類型的CellTemplate，這里返還一個TreeViewCell（需要自定義）
/// <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類
上面TreeViewColumn重寫了CellTemplate，返回的就是自定義的TreeViewCell，這里就是具體實現(xiàn)其邏輯。一般來說選擇樹控件的節(jié)點后，返回的是一個文本信息，是文本類型，可以繼承DataGridViewTextBoxCell,并重寫InitializeEditingControl來進(jìn)行自定義的DataGridView.EditingControl （編輯控件）。
public class TreeViewCell : DataGridViewTextBoxCell { public TreeViewCell() : base() { //初始設(shè)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類
TreeViewEditingControl為編輯控件，當(dāng)用戶編輯TreeViewCell時，顯示的為樹編輯控件，需要繼承TreeView，同時實現(xiàn)IDataGridViewEditingControl接口，實現(xiàn)以下方法：
public class TreeViewEditingControl : TreeView, IDataGridViewEditingControl { DataGridView dataGridView; private bool valueChanged = false; int rowIndex; public TreeViewEditingControl() { try { //必須加Roots.tree.Nodes[].Clone() 否則報錯 不能在多處增添或插入項，必須首先將其從當(dāng)前位置移除或?qū)⑵淇寺? 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); } } 為了在不同類之間傳遞參數(shù)，定義一個全局靜態(tài)類：
/// <summary> /// 靜態(tài)類的靜態(tài)屬性，用于在不同class間傳遞參數(shù) /// </summary> public static class Roots { //從前臺綁定樹 public static TreeView tree = null; } 完整代碼為：
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> /// 靜態(tài)類的靜態(tài)屬性，用于在不同class間傳遞參數(shù) /// </summary> public static class Roots { //從前臺綁定樹 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() { //初始設(shè)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 { //必須加Roots.tree.Nodes[].Clone() 否則報錯 不能在多處增添或插入項，必須首先將其從當(dāng)前位置移除或?qū)⑵淇寺? 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); } } }
當(dāng)編輯無誤后，可以在添加列的時候看到TreeViewColumn類型。此類型暴露出一個_root屬性，可以綁定外部的一個帶數(shù)據(jù)的TreeView。
運行代碼，單擊單元格，進(jìn)入編輯狀態(tài)，可以看到如下界面：
以上內(nèi)容是小編給大家介紹的C#自定義DataGridViewColumn顯示TreeView 的全部敘述，希望大家喜歡。
