C#如何自定义DataGridViewColumn来显示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）

1     /// <summary>
2     /// Host TreeView In DataGridView Cell
3     /// </summary>
4    public class TreeViewColumn : DataGridViewColumn
5     {
6         public TreeViewColumn()
7             : base(new TreeViewCell())
8         {
9         }
10         [Description("Set TreeView Root in DataGridView Cell"), Category("TreeView")]
11         public TreeView _root
12         {
13             get{return Roots.tree;}
14             set{Roots.tree=value;}
15         }
16         public override DataGridViewCell CellTemplate
17         {
18             get
19             {
20                 return base.CellTemplate;
21             }
22             set
23             {
24                 // Ensure that the cell used for the template is a TreeViewCell.
25                 if (value != null &&
26                     !value.GetType().IsAssignableFrom(typeof(TreeViewCell)))
27                 {
28                     throw new InvalidCastException("Must be a TreeViewCell");
29                 }
30                 base.CellTemplate = value;
31             }
32         }
33     }

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）。

1   public class TreeViewCell : DataGridViewTextBoxCell
2     {
3
4         public TreeViewCell()
5             : base()
6         {
7
8             //初始设置
9         }
10
11         public override void InitializeEditingControl(int rowIndex, object
12             initialFormattedValue, DataGridViewCellStyle dataGridViewCellStyle)
13         {
14             // Set the value of the editing control to the current cell value.
15             base.InitializeEditingControl(rowIndex, initialFormattedValue,
16                 dataGridViewCellStyle);
17             TreeViewEditingControl ctl =
18                 DataGridView.EditingControl as TreeViewEditingControl;
19             // Use the default row value when Value property is null.
20             if (this.Value == null)
21             {
22
23                 ctl.SelectedNode =new TreeNode( this.DefaultNewRowValue.ToString());
24             }
25             else
26             {
27                 ctl.SelectedNode = new TreeNode(this.Value.ToString());
28             }
29         }
30
31         public override Type EditType
32         {
33             get
34             {
35                 // Return the type of the editing control that CalendarCell uses.
36                 return typeof(TreeViewEditingControl);
37             }
38         }
39
40         public override Type ValueType
41         {
42             get
43             {
44                 // Return the type of the value that CalendarCell contains.
45                 return typeof(String);
46             }
47         }
48
49         public override object DefaultNewRowValue
50         {
51             get
52             {
53                 // Use the current date and time as the default value.
54                 return "";
55             }
56         }
57     }

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：

1 public class TreeViewEditingControl : TreeView, IDataGridViewEditingControl
2     {
3         DataGridView dataGridView;
4         private bool valueChanged = false;
5         int rowIndex;
6         public TreeViewEditingControl()
7         {
8             try
9             {
10                 //必须加Roots.tree.Nodes[0].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
11                 this.Nodes.Add(Roots.tree.Nodes[0].Clone() as TreeNode);
12                 this.SelectedNode = this.Nodes[0];
13
14
15             }
16             catch (Exception ex)
17             {
18                 MessageBox.Show(ex.Message);
19             }
20
21
22         }
23
24         // Implements the IDataGridViewEditingControl.EditingControlFormattedValue
25         // property.
26         public object EditingControlFormattedValue
27         {
28             get
29             {
30                 return this.SelectedNode.Text;
31             }
32             set
33             {
34                 if (value is String)
35                 {
36                     try
37                     {
38                         // This will throw an exception of the string is
39                         // null, empty, or not in the format of a date.
40                         this.SelectedNode = new TreeNode((String)value);
41
42                     }
43                     catch
44                     {
45                         // In the case of an exception, just use the
46                         // default value so we're not left with a null
47                         // value.
48                         this.SelectedNode = new TreeNode("");
49                     }
50                 }
51             }
52         }
53
54         // Implements the
55         // IDataGridViewEditingControl.GetEditingControlFormattedValue method.
56         public object GetEditingControlFormattedValue(
57             DataGridViewDataErrorContexts context)
58         {
59             return EditingControlFormattedValue;
60         }
61
62         // Implements the
63         // IDataGridViewEditingControl.ApplyCellStyleToEditingControl method.
64         public void ApplyCellStyleToEditingControl(
65             DataGridViewCellStyle dataGridViewCellStyle)
66         {
67             this.Font = dataGridViewCellStyle.Font;
68             this.ForeColor = dataGridViewCellStyle.ForeColor;
69             this.BackColor = dataGridViewCellStyle.BackColor;
70         }
71
72         // Implements the IDataGridViewEditingControl.EditingControlRowIndex
73         // property.
74         public int EditingControlRowIndex
75         {
76             get
77             {
78                 return rowIndex;
79             }
80             set
81             {
82                 rowIndex = value;
83             }
84         }
85
86         // Implements the IDataGridViewEditingControl.EditingControlWantsInputKey
87         // method.
88         public bool EditingControlWantsInputKey(
89             Keys key, bool dataGridViewWantsInputKey)
90         {
91             // Let the TreeViewPicker handle the keys listed.
92             switch (key & Keys.KeyCode)
93             {
94                 case Keys.Left:
95                 case Keys.Up:
96                 case Keys.Down:
97                 case Keys.Right:
98                 case Keys.Home:
99                 case Keys.End:
100                 case Keys.PageDown:
101                 case Keys.PageUp:
102                     return true;
103                 default:
104                     return !dataGridViewWantsInputKey;
105             }
106         }
107
108         // Implements the IDataGridViewEditingControl.PrepareEditingControlForEdit
109         // method.
110         public void PrepareEditingControlForEdit(bool selectAll)
111         {
112             // No preparation needs to be done.
113         }
114
115         // Implements the IDataGridViewEditingControl
116         // .RepositionEditingControlOnValueChange property.
117         public bool RepositionEditingControlOnValueChange
118         {
119             get
120             {
121                 return false;
122             }
123         }

124
125         // Implements the IDataGridViewEditingControl
126         // .EditingControlDataGridView property.
127         public DataGridView EditingControlDataGridView
128         {
129             get
130             {
131                 return dataGridView;
132             }
133             set
134             {
135                 dataGridView = value;
136             }
137         }
138
139         // Implements the IDataGridViewEditingControl
140         // .EditingControlValueChanged property.
141         public bool EditingControlValueChanged
142         {
143             get
144             {
145                 return valueChanged;
146             }
147             set
148             {
149                 valueChanged = value;
150             }
151         }
152
153         // Implements the IDataGridViewEditingControl
154         // .EditingPanelCursor property.
155         public Cursor EditingPanelCursor
156         {
157             get
158             {
159                 return base.Cursor;
160             }
161         }
162
163         protected override void OnAfterExpand(TreeViewEventArgs e)
164         {
165             base.OnAfterExpand(e);
166             this.dataGridView.Columns[this.dataGridView.CurrentCell.ColumnIndex].Width = this.Width+10;
167             this.dataGridView.Rows[this.dataGridView.CurrentCell.RowIndex].Height = this.Height+20;
168
169         }
170         protected override void OnAfterSelect(TreeViewEventArgs e)
171         {
172             // Notify the DataGridView that the contents of the cell
173             // have changed.
174             valueChanged = true;
175             this.EditingControlDataGridView.NotifyCurrentCellDirty(true);
176             base.OnAfterSelect(e);
177
178         }
179
180     }

　　为了在不同类之间传递参数，定义一个全局静态类：

1   /// <summary>
2     /// 静态类的静态属性，用于在不同class间传递参数
3     /// </summary>
4     public static class Roots
5     {
6         //从前台绑定树
7        public static TreeView tree = null;
8     }

完整代码为：


 View
Code



　　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：



 

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