ASP.NET生成树形显示的GridView实现思路

时间：2021-05-28

目的：生成树形结构的表格数据（EasyUI也有TreeGrid，此处只是提供一个思路），可以扩展单击展开/收缩节点
图例：

类代码：
复制代码 代码如下:
using System;
using System.Data;
/// <summary>
///GridViewHelper 的摘要说明
/// </summary>
public class GridViewHelper
{
private string gridline; //连接线
private DataTable dt; //传入的DataTable
private DataTable dtOut; //输出的DataTable
private DataRow row; //用于从DataView取数据并增加到dtOut
public GridViewHelper()
{
//
//TODO: 在此处添加构造函数逻辑
//
}
/// <summary>
/// 生成树形结构的DataTable
/// </summary>
/// <param name="datatable">原始数据表</param>
/// <param name="parentField">上级节点关键字段</param>
/// <param name="parentValue">上级节点值</param>
/// <param name="keyField">本节点关键字段</param>
/// <param name="textField">显示的文本字段</param>
/// <param name="sortString">排序字符串</param>
/// <returns>处理后的DataTable</returns>
public DataTable GetGridViewTreeData(DataTable datatable, string parentField, string parentValue, string keyField, string textField, string sortString)
{
datatable.Columns.Add("level", Type.GetType("System.Int32"));
dt = datatable;
dtOut = datatable.Clone();
resetTextField(parentField, parentValue, keyField, textField, sortString, 0);
return dtOut;
}
/// <summary>
/// 递归生成新的节点名称(带连接线)
/// </summary>
/// <param name="parentValueField">上级节点关键字段</param>
/// <param name="parentValue">上级节点值</param>
/// <param name="keyField">本节点关键字段</param>
/// <param name="textField">显示出来的文本字段</param>
/// <param name="sortString">排序字符串</param>
/// <param name="level">树深度</param>
/// <returns></returns>
private void resetTextField(string parentValueField, string parentValue, string keyField, string textField, string sortString,int level)
{
DataView dv = new DataView(dt, parentValueField + "='" + parentValue + "'", sortString, DataViewRowState.CurrentRows);
int a = dv.Count;
if (dv.Count == 0)
{
return;
}
for (int i = 0; i < a; i++)
{
gridline = "";
dv.RowFilter = parentValueField + "='" + parentValue + "'";
dv.Sort = sortString;
getTreeLine(parentValueField, dv[i][parentValueField].ToString(), keyField, dv[i][keyField].ToString(), sortString);
dv.RowFilter = parentValueField + "='" + parentValue + "'";
dv.Sort = sortString;
row = dtOut.NewRow();
for (int c = 0; c < dv[i].Row.ItemArray.Length; c++)
{
row[c] = dv[i][c];
}
dtOut.Rows.Add(row);
dtOut.Rows[dtOut.Rows.Count - 1][textField] = gridline + (i == a - 1 ? "┗" : "┣") + dv[i][textField].ToString();
dtOut.Rows[dtOut.Rows.Count - 1]["level"] = level;
resetTextField(parentValueField, dv[i][keyField].ToString(), keyField, textField, sortString,level+1);
}
dv.Dispose();
}
/// <summary>
/// 回溯生成树的连接线
/// </summary>
/// <param name="parentValueField">上级节点关键字段</param>
/// <param name="parentValue">上级节点值</param>
/// <param name="keyField">本节点关键字段</param>
/// <param name="nodeKey">本节点值</param>
/// <param name="sortString">排序字符串</param>
/// <returns></returns>
private void getTreeLine(string parentValueField, string parentValue, string keyField, string nodeKey, string sortString)
{
//选择父层节点
DataView dv = new DataView(dt, keyField + "='" + parentValue + "'", sortString, DataViewRowState.CurrentRows);
if (dv.Count > 0)
{
//选择父节点同级节点
dv.RowFilter = parentValueField + "='" + dv[0][parentValueField].ToString() + "'";
dv.Sort = sortString;
for (int j = 0; j < dv.Count; j++)
{
if (dv[j][keyField].ToString() == parentValue)
{
if (j == dv.Count - 1)
{
gridline = "　" + gridline;
}
else
{
gridline = "┃" + gridline;
}
}
}
getTreeLine(parentValueField, dv[0][parentValueField].ToString(), keyField, dv[0][keyField].ToString(), sortString);
}
dv.Dispose();
}
}

HTML示例代码：
复制代码 代码如下:
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="GridViewTree.aspx.cs" Inherits="GridViewTree" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>生成树形显示的GridView</title>
<style type="text/css">
body
{
line-height: 16px;
font-size: 14px;
}
td
{
padding: 0 2px;
}
</style>
</head>
<body>
<form id="form1" runat="server">
<table>
<tr>
<td valign="top">
<asp:DropDownList ID="DropDownList1" runat="server">
</asp:DropDownList>
</td>
<td>
<asp:GridView ID="GridView1" runat="server" BorderWidth="1px" CellPadding="3" GridLines="Vertical"
AutoGenerateColumns="False" BackColor="White" BorderColor="#E7E7FF" BorderStyle="None">
<AlternatingRowStyle BackColor="#F7F7F7" />
<Columns>
<asp:BoundField DataField="ConText" HeaderText="文本" />
<asp:BoundField DataField="id" HeaderText="ID">
<ItemStyle HorizontalAlign="Right" Width="80px" />
</asp:BoundField>
<asp:BoundField DataField="ParentID" HeaderText="父ID">
<ItemStyle HorizontalAlign="Right" Width="80px" />
</asp:BoundField>
<asp:BoundField DataField="level" HeaderText="Level">
<ItemStyle HorizontalAlign="Right" Width="80px" />
</asp:BoundField>
</Columns>
<FooterStyle BackColor="#B5C7DE" ForeColor="#4A3C8C" />
<HeaderStyle BackColor="#4A3C8C" Font-Bold="True" ForeColor="#F7F7F7" />
<PagerStyle BackColor="#E7E7FF" ForeColor="#4A3C8C" HorizontalAlign="Right" />
<RowStyle BackColor="#E7E7FF" ForeColor="#4A3C8C" />
<SelectedRowStyle BackColor="#738A9C" Font-Bold="True" ForeColor="#F7F7F7" />
<SortedAscendingCellStyle BackColor="#F4F4FD" />
<SortedAscendingHeaderStyle BackColor="#5A4C9D" />
<SortedDescendingCellStyle BackColor="#D8D8F0" />
<SortedDescendingHeaderStyle BackColor="#3E3277" />
</asp:GridView>
</td>
</tr>
</table>
</form>
</body>
</html>

后台代码：
复制代码 代码如下:
DataTable dt = gvHelper.GetGridViewTreeData(datatable, "ParentID", "1", "ID", "ConText", "ConText asc");
GridView1.DataSource = dt;
GridView1.DataBind();
DropDownList1.Items.Add("");
DropDownList1.AppendDataBoundItems = true;
DropDownList1.DataSource = dt;
DropDownList1.DataTextField = "ConText";
DropDownList1.DataValueField = "ID";
DropDownList1.DataBind();

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