C#自定義DataGridViewColumn顯示TreeView

2020-01-24 01:20:19

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我們可以自定義DataGridView的DataGridViewColumn來實現自定義的列，下面介紹一下如何通過擴展DataGridViewColumn來實現一個TreeViewColumn

1.TreeViewColumn類

　TreeViewColumn繼承自DataGridViewColumn，為了動態給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，這里就是具體實現其邏輯。一般來說選擇樹控件的節點后，返回的是一個文本信息，是文本類型，可以繼承DataGridViewTextBoxCell,并重寫InitializeEditingControl來進行自定義的DataGridView.EditingControl （編輯控件）。

 public class TreeViewCell : DataGridViewTextBoxCell  {   public TreeViewCell()    : base()   {    //初始設置   }   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，當用戶編輯TreeViewCell時，顯示的為樹編輯控件，需要繼承TreeView，同時實現IDataGridViewEditingControl接口，實現以下方法：

 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，必須首先將其從當前位置移除或將其克隆     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);   }  }

　　為了在不同類之間傳遞參數，定義一個全局靜態類：

 /// <summary>  /// 靜態類的靜態屬性，用于在不同class間傳遞參數  /// </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>  /// 靜態類的靜態屬性，用于在不同class間傳遞參數  /// </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，必須首先將其從當前位置移除或將其克隆     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);   }  } }