asp.net本身就给我们提供了很多控件,而且不少控件开发公司也为我们提供了丰富漂亮的控件；但仍然不能满足我这样的懒人在实际项目中的需要,所以就需要学会自己来开发控件。因为我不想重复工作,所以要创建它,我自己是很喜欢控件开发，只不过目前还是一个小菜。
前些时间在园子里看到有位朋友写也了一个DropDownTreeList控件,说实话写的很是不错。今天也贴出我在项目中写的DropDownTreeList控件，以此来和园子里喜欢控件开发的朋友共同进步。
是不是有朋友在说：“少废话了，代码贴出来看看先”。好，那就贴出代码先：
好的，图来了。效果1：
好的，图来了。效果2：
使用方法：
string SQl = "select * from SYS_T_Menu";
DataTable dt = SqlHelper.ReturnDataTable(SQl);
DropDownTreeList1.NodeTextField = "Menu_Name";
DropDownTreeList1.NodeValueField = "Menu_ID";
DropDownTreeList1.ParentFiledName = "Menu_Father_ID";
DropDownTreeList1.DataSource = dt;
DropDownTreeList1.DataBind();
前些时间在园子里看到有位朋友写也了一个DropDownTreeList控件,说实话写的很是不错。今天也贴出我在项目中写的DropDownTreeList控件，以此来和园子里喜欢控件开发的朋友共同进步。
是不是有朋友在说：“少废话了，代码贴出来看看先”。好，那就贴出代码先：
1
/// <summary>
2
/// 下拉树形框控件。
3
/// </summary>
4
[DefaultProperty("Text"), ToolboxData("<{0}:DropDownTreeList runat=server></{0}:DropDownTreeList>")]
5 public class DropDownTreeList : WebControl, IPostBackDataHandler, IPostBackEventHandler
6 {
7
8
/// <summary>
9 /// 下拉列表框控件变量
10
/// </summary>
11 public System.Web.UI.WebControls.DropDownList TypeID = new System.Web.UI.WebControls.DropDownList();
12
13
14 /// <summary>
15 /// 构造函数
16 /// </summary>
17 public DropDownTreeList(): base()
18 {
19 this.BorderStyle = BorderStyle.Groove;
20 this.BorderWidth = 1;
21 }
22
23 /// <summary>
24 /// 构造函数
25 /// </summary>
26 /// <param name="dt"></param>
27 public DropDownTreeList(DataTable dt): this()
28 {
29 BuildTree(dt);
30 }
31
32 /// <summary>
33 /// 构造函数
34 /// </summary>
35 /// <param name="selectid">选择项</param>
36 /// <param name="dt"></param>
37 public DropDownTreeList(string selectid,DataTable dt): this(dt)
38 {
39 this.TypeID.SelectedValue = selectid;
40 }
41
42 /// <summary>
43 /// 创建树
44 /// </summary>
45 /// <param name="dt"></param>
46 public void BuildTree(DataTable dt)
47 {
48 if(this.ParentFiledName.Trim()=="")
49 {
50 throw new Exception("父字段名称不能为空");
51 }
52 if (this.NodeTextField.Trim() == "")
53 {
54 throw new Exception("节点文本字段名称不能为空");
55 }
56 if(this.NodeValueField.Trim()=="")
57 {
58 throw new Exception("节点值字段名称不能为空");
59 }
60 string SelectedType = "0";
61
62 TypeID.SelectedValue = SelectedType;
63 this.Controls.Add(TypeID);
64 TypeID.Items.Clear();
65 //加载树
66 TypeID.Items.Add(new ListItem("请选择 ", "0"));
67 DataRow[] drs = dt.Select(this.ParentFiledName + "=0");
68 foreach (DataRow r in drs)
69 {
70 TypeID.Items.Add(new ListItem(r[NodeTextField].ToString(), r[NodeValueField].ToString()));
71 string blank=StyleDropTree.DropDownTreeList_Style(DropTreeStyle);
72 BindNode(r[NodeValueField].ToString(), dt, blank);
73 }
74
75 TypeID.DataBind();
76 }
77
78 private string _nodeValueField="";
79 /// <summary>
80 /// 节点值字段
81 /// </summary>
82 [Bindable(true), Browsable(true), Category("数据"), DefaultValue("")]
83 public string NodeValueField
84 {
85 get
86 {
87 try
88 {
89 return _nodeValueField;
90 }
91 catch
92 {
93 throw new Exception();
94 }
95
96 }
97 set
98 {
99 this._nodeValueField = value;
100 }
101 }
102
103 private string _nodeTextField="";
104 /// <summary>
105 /// 节点文本字段
106 /// </summary>
107 [Bindable(true), Browsable(true), Category("数据"), DefaultValue("")]
108 public string NodeTextField
109 {
110 get
111 {
112 try
113 {
114 return _nodeTextField;
115 }
116 catch
117 {
118 throw new Exception();
119 }
120
121 }
122 set
123 {
124 this._nodeTextField = value;
125 }
126 }
127
128 /// <summary>
129 /// 创建树
130 /// </summary>
131 /// <param name="sqlstring">查询字符串</param>
132 /// <param name="selectid">选取项</param>
133 public void BuildTree(string selectid,DataTable dt)
134 {
135 BuildTree(dt);
136 this.TypeID.SelectedValue = selectid;
137 }
138
139 /// <summary>
140 /// 创建树结点
141 /// </summary>
142 /// <param name="sonparentid">当前数据项</param>
143 /// <param name="dt">数据表</param>
144 /// <param name="blank">空白符</param>
145 private void BindNode(string sonparentid, DataTable dt, string blank)
146 {
147 DataRow[] drs = dt.Select(this.ParentFiledName + "=" + sonparentid);
148
149 foreach (DataRow r in drs)
150 {
151 string nodevalue = r[NodeValueField].ToString();
152 string text = r[NodeTextField].ToString();
153 if (StyleDropTree.DropDownTreeList_Style(DropTreeStyle) == "├─『")
154 {
155 text = blank + "" + text + "』";
156 }
157 else
158 {
159 text = blank + "" + text + "";
160 }
161 TypeID.Items.Add(new ListItem(text, nodevalue));
162 string blankNode = HttpUtility.HtmlDecode(" ") + blank;
163 BindNode(nodevalue, dt, blankNode);
164 }
165 }
166
167
168 /// <summary>
169 /// 当前选择项的值
170 /// </summary>
171 [Bindable(false), Browsable(false), Category("数据"), DefaultValue("")]
172 public string SelectedValue
173 {
174 get
175 {
176 return this.TypeID.SelectedValue;
177 }
178
179 set
180 {
181 this.TypeID.SelectedValue = value;
182 }
183 }
184
185 /// <summary>
186 /// 当前选择项的文本
187 /// </summary>
188 [Bindable(false), Browsable(false), Category("数据"), DefaultValue("")]
189 public string SelectedText
190 {
191 get
192 {
193 try
194 {
195 string NodeText = this.TypeID.SelectedItem.Text.Trim();
196 int i = 0;
197 if (StyleDropTree.DropDownTreeList_Style(DropTreeStyle) == "├─『")
198 {
199 i = NodeText.IndexOf("『");
200 return NodeText.Substring(i + 1, NodeText.Length - i - 2);
201 }
202 else
203 {
204 return NodeText.Trim();
205 }
206
207 }
208 catch
209 {
210 return "";
211 }
212
213 }
214 set
215 {
216 this.TypeID.SelectedItem.Text=value;
217 }
218 }
219 /// <summary>
220 /// 父字段名称
221 /// </summary>
222 private string m_parentid = "";
223 [Bindable(true), Category("数据"), DefaultValue("")]
224 public string ParentFiledName
225 {
226 get
227 {
228 return m_parentid;
229 }
230
231 set
232 {
233 m_parentid = value;
234 }
235 }
236
237 /// <summary>
238 /// 当某选项被选中后,获取焦点的控件ID(如提交按钮等)
239 /// </summary>
240 [Bindable(true), Category("数据"), DefaultValue("")]
241 public string SetFocusButtonID
242 {
243 get
244 {
245 object o = ViewState[this.ClientID + "_SetFocusButtonID"];
246 return (o == null) ? "" : o.ToString();
247 }
248 set
249 {
250 ViewState[this.ClientID + "_SetFocusButtonID"] = value;
251 if (value != "")
252 {
253 this.TypeID.Attributes.Add("onChange", "document.getElementById('" + value + "').focus();");
254 }
255 }
256 }
257
258 /// <summary>
259 /// 获取或设置数据源
260 /// </summary>
261 private object _dataSource;
262 [Bindable(true),Category("Data"),DefaultValue(null),Description("数据"),DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
263 public virtual object DataSource
264 {
265 get
266 {
267 return _dataSource;
268 }
269 set
270 {
271 if ((value == null) || (value is IListSource) || (value is IEnumerable))
272 {
273 _dataSource = value;
274 }
275 else
276 {
277 throw new ArgumentException();
278 }
279 }
280 }
281
282 public override void DataBind()
283 {
284 base.OnDataBinding(EventArgs.Empty);
285 DataTable table = (DataTable)this.DataSource;
286 BuildTree(table);
287 }
288
289
290 private StyleLook _styleLook;
291 /// <summary>
292 /// 设置控件的样式
293 /// </summary>
294 [Bindable(true), Category("样式"), DefaultValue("")]
295 public StyleLook DropTreeStyle
296 {
297
298 set { _styleLook = value; }
299 get { return _styleLook; }
300 }
301 /// <summary>
302 /// 输出html,在浏览器中显示控件
303 /// </summary>
304 /// <param name="output"> 要写出到的 HTML 编写器 </param>
305 protected override void Render(HtmlTextWriter output)
306 {
307 if (this.HintInfo != "")
308 {
309 output.WriteBeginTag("span id=\"" + this.ClientID + "\" onmouseover=\"showhintinfo(this," + this.HintLeftOffSet + "," + this.HintTopOffSet + ",'" + this.HintTitle + "','" + this.HintInfo + "','" + this.HintHeight + "','" + this.HintShowType + "');\" onmouseout=\"hidehintinfo();\">");
310 }
311
312 RenderChildren(output);
313
314 if (this.HintInfo != "")
315 {
316 output.WriteEndTag("span");
317 }
318 }
319
320
321
322
IPostBackDataHandler 成员
“连个效果图没有，就让人看你那烂代码。来个图先？”，有朋友又在喊了。/// <summary>
2
/// 下拉树形框控件。3
/// </summary>4
[DefaultProperty("Text"), ToolboxData("<{0}:DropDownTreeList runat=server></{0}:DropDownTreeList>")]5
public class DropDownTreeList : WebControl, IPostBackDataHandler, IPostBackEventHandler6
{
7
8
/// <summary>9
/// 下拉列表框控件变量10
/// </summary>11
public System.Web.UI.WebControls.DropDownList TypeID = new System.Web.UI.WebControls.DropDownList();12
13
14
/// <summary>15
/// 构造函数16
/// </summary>17
public DropDownTreeList(): base()18
{19
this.BorderStyle = BorderStyle.Groove;20
this.BorderWidth = 1;21
}22
23
/// <summary>24
/// 构造函数25
/// </summary>26
/// <param name="dt"></param>27
public DropDownTreeList(DataTable dt): this()28
{29
BuildTree(dt);30
}31
32
/// <summary>33
/// 构造函数34
/// </summary>35
/// <param name="selectid">选择项</param>36
/// <param name="dt"></param>37
public DropDownTreeList(string selectid,DataTable dt): this(dt)38
{39
this.TypeID.SelectedValue = selectid;40
}41
42
/// <summary>43
/// 创建树44
/// </summary>45
/// <param name="dt"></param>46
public void BuildTree(DataTable dt)47
{48
if(this.ParentFiledName.Trim()=="")49
{50
throw new Exception("父字段名称不能为空");51
}52
if (this.NodeTextField.Trim() == "")53
{54
throw new Exception("节点文本字段名称不能为空");55
}56
if(this.NodeValueField.Trim()=="")57
{58
throw new Exception("节点值字段名称不能为空");59
}60
string SelectedType = "0";61
62
TypeID.SelectedValue = SelectedType;63
this.Controls.Add(TypeID);64
TypeID.Items.Clear();65
//加载树66
TypeID.Items.Add(new ListItem("请选择 ", "0"));67
DataRow[] drs = dt.Select(this.ParentFiledName + "=0");68
foreach (DataRow r in drs)69
{ 70
TypeID.Items.Add(new ListItem(r[NodeTextField].ToString(), r[NodeValueField].ToString()));71
string blank=StyleDropTree.DropDownTreeList_Style(DropTreeStyle);72
BindNode(r[NodeValueField].ToString(), dt, blank);73
}74
75
TypeID.DataBind();76
}77
78
private string _nodeValueField="";79
/// <summary>80
/// 节点值字段81
/// </summary>82
[Bindable(true), Browsable(true), Category("数据"), DefaultValue("")]83
public string NodeValueField84
{85
get86
{87
try88
{89
return _nodeValueField;90
}91
catch92
{93
throw new Exception();94
}95
96
}97
set98
{99
this._nodeValueField = value;100
}101
}102
103
private string _nodeTextField="";104
/// <summary>105
/// 节点文本字段106
/// </summary>107
[Bindable(true), Browsable(true), Category("数据"), DefaultValue("")]108
public string NodeTextField109
{110
get111
{112
try113
{114
return _nodeTextField;115
}116
catch117
{118
throw new Exception();119
}120
121
}122
set123
{124
this._nodeTextField = value;125
}126
}127
128
/// <summary>129
/// 创建树130
/// </summary>131
/// <param name="sqlstring">查询字符串</param>132
/// <param name="selectid">选取项</param>133
public void BuildTree(string selectid,DataTable dt)134
{135
BuildTree(dt);136
this.TypeID.SelectedValue = selectid;137
}138
139
/// <summary>140
/// 创建树结点141
/// </summary>142
/// <param name="sonparentid">当前数据项</param>143
/// <param name="dt">数据表</param>144
/// <param name="blank">空白符</param>145
private void BindNode(string sonparentid, DataTable dt, string blank)146
{147
DataRow[] drs = dt.Select(this.ParentFiledName + "=" + sonparentid);148
149
foreach (DataRow r in drs)150
{151
string nodevalue = r[NodeValueField].ToString();152
string text = r[NodeTextField].ToString();153
if (StyleDropTree.DropDownTreeList_Style(DropTreeStyle) == "├─『")154
{155
text = blank + "" + text + "』";156
}157
else158
{159
text = blank + "" + text + "";160
}161
TypeID.Items.Add(new ListItem(text, nodevalue));162
string blankNode = HttpUtility.HtmlDecode(" ") + blank;163
BindNode(nodevalue, dt, blankNode);164
}165
}166
167
168
/// <summary>169
/// 当前选择项的值170
/// </summary>171
[Bindable(false), Browsable(false), Category("数据"), DefaultValue("")]172
public string SelectedValue173
{174
get175
{176
return this.TypeID.SelectedValue;177
}178
179
set180
{181
this.TypeID.SelectedValue = value;182
}183
}184
185
/// <summary>186
/// 当前选择项的文本187
/// </summary>188
[Bindable(false), Browsable(false), Category("数据"), DefaultValue("")]189
public string SelectedText190
{191
get 192
{193
try194
{195
string NodeText = this.TypeID.SelectedItem.Text.Trim();196
int i = 0;197
if (StyleDropTree.DropDownTreeList_Style(DropTreeStyle) == "├─『")198
{199
i = NodeText.IndexOf("『");200
return NodeText.Substring(i + 1, NodeText.Length - i - 2);201
}202
else203
{204
return NodeText.Trim();205
}206
207
}208
catch209
{210
return "";211
}212
213
}214
set 215
{ 216
this.TypeID.SelectedItem.Text=value;217
}218
}219
/// <summary>220
/// 父字段名称221
/// </summary>222
private string m_parentid = "";223
[Bindable(true), Category("数据"), DefaultValue("")]224
public string ParentFiledName225
{226
get227
{228
return m_parentid;229
}230
231
set232
{233
m_parentid = value;234
}235
}236
237
/// <summary>238
/// 当某选项被选中后,获取焦点的控件ID(如提交按钮等)239
/// </summary>240
[Bindable(true), Category("数据"), DefaultValue("")]241
public string SetFocusButtonID242
{243
get244
{245
object o = ViewState[this.ClientID + "_SetFocusButtonID"];246
return (o == null) ? "" : o.ToString();247
}248
set249
{250
ViewState[this.ClientID + "_SetFocusButtonID"] = value;251
if (value != "")252
{253
this.TypeID.Attributes.Add("onChange", "document.getElementById('" + value + "').focus();");254
}255
}256
}257
258
/// <summary>259
/// 获取或设置数据源260
/// </summary>261
private object _dataSource;262
[Bindable(true),Category("Data"),DefaultValue(null),Description("数据"),DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]263
public virtual object DataSource264
{265
get266
{267
return _dataSource;268
}269
set270
{271
if ((value == null) || (value is IListSource) || (value is IEnumerable))272
{273
_dataSource = value;274
}275
else276
{277
throw new ArgumentException();278
}279
}280
}281
282
public override void DataBind()283
{ 284
base.OnDataBinding(EventArgs.Empty);285
DataTable table = (DataTable)this.DataSource;286
BuildTree(table);287
}288
289
290
private StyleLook _styleLook;291
/// <summary>292
/// 设置控件的样式293
/// </summary>294
[Bindable(true), Category("样式"), DefaultValue("")]295
public StyleLook DropTreeStyle296
{297
298
set { _styleLook = value; }299
get { return _styleLook; }300
}301
/// <summary>302
/// 输出html,在浏览器中显示控件303
/// </summary>304
/// <param name="output"> 要写出到的 HTML 编写器 </param>305
protected override void Render(HtmlTextWriter output)306
{307
if (this.HintInfo != "")308
{309
output.WriteBeginTag("span id=\"" + this.ClientID + "\" onmouseover=\"showhintinfo(this," + this.HintLeftOffSet + "," + this.HintTopOffSet + ",'" + this.HintTitle + "','" + this.HintInfo + "','" + this.HintHeight + "','" + this.HintShowType + "');\" onmouseout=\"hidehintinfo();\">");310
}311
312
RenderChildren(output);313
314
if (this.HintInfo != "")315
{316
output.WriteEndTag("span");317
}318
}319
320
321
322
IPostBackDataHandler 成员好的，图来了。效果1：
好的，图来了。效果2：
使用方法：
string SQl = "select * from SYS_T_Menu";
DataTable dt = SqlHelper.ReturnDataTable(SQl);
DropDownTreeList1.NodeTextField = "Menu_Name";
DropDownTreeList1.NodeValueField = "Menu_ID";
DropDownTreeList1.ParentFiledName = "Menu_Father_ID";
DropDownTreeList1.DataSource = dt;
DropDownTreeList1.DataBind();
