using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace _2
{
public partial class KnowledgeTree : Form
{
private string connectionString = "Data Source=localhost;Initial Catalog=pointnote;Integrated Security=True;";
// 声明控件变量
private SplitContainer mainSplitContainer;
private TreeView treeView;
private TextBox txtName1;
private TextBox txtSubject1;
private RichTextBox txtContent1;
public KnowledgeTree()
{
InitializeComponent();
InitializeUI(); // 添加初始化调用
LoadKnowledgeTree(); // 添加树加载
}
// 初始化界面控件
private void InitializeUI()
{
{
// 主分割容器
mainSplitContainer = new SplitContainer
{
Dock = DockStyle.Fill,
SplitterDistance = 300
};
this.Controls.Add(mainSplitContainer);
// 树视图
treeView = new TreeView
{
Dock = DockStyle.Fill,
ImageList = CreateImageList(),
ShowNodeToolTips = true
};
mainSplitContainer.Panel1.Controls.Add(treeView);
// 详情面板
Panel detailPanel = new Panel { Dock = DockStyle.Fill };
mainSplitContainer.Panel2.Controls.Add(detailPanel);
// 详情控件
txtName1 = new TextBox { Location = new Point(10, 30), Width = 200 };
txtSubject1 = new TextBox { Location = new Point(10, 70), Width = 200 };
txtContent1 = new RichTextBox { Location = new Point(10, 110), Size = new Size(400, 200) };
btnSave = new Button { Text = "保存", Location = new Point(10, 320) };
btnSave.Click += SaveKnowledge; // 绑定保存事件
detailPanel.Controls.AddRange(new Control[] {
new Label { Text = "名称", Location = new Point(10, 10) },
txtName1,
new Label { Text = "学科", Location = new Point(10, 50) },
txtSubject,
new Label { Text = "内容", Location = new Point(10, 90) },
txtContent1,
btnSave
});
}
}
private ImageList CreateImageList()
{
ImageList images = new ImageList();
images.ColorDepth = ColorDepth.Depth32Bit;
images.ImageSize = new Size(24, 24);
// 使用系统图标（实际应用中应使用自定义图标）
images.Images.Add(SystemIcons.Information); // 0: 普通节点
images.Images.Add(SystemIcons.Warning); // 1: 重要节点
images.Images.Add(SystemIcons.Question); // 2: 问题节点
return images;
}
// 加载知识点树状图
private void LoadKnowledgeTree()
{
TreeView treeView1 = this.Controls[0] is SplitContainer sc ?
(TreeView)sc.Panel1.Controls[0] : null;
if (treeview == null) return;
treeview.Nodes.Clear();
treeview.BeginUpdate();
try
{
// 获取所有知识点
DataTable points = GetKnowledgePoints();
// 创建节点字典
var nodeDict = new Dictionary<int, TreeNode>();
// 第一遍：创建所有节点
foreach (DataRow row in points.Rows)
{
int pid = Convert.ToInt32(row["Pid"]);
string nodeText = $"{row["Pname"]} ({row["Stype"]})";
TreeNode node = new TreeNode(nodeText)
{
Name = pid.ToString(),
Tag = row, // 存储整行数据
ToolTipText = row["Content"].ToString(),
ImageIndex = GetNodeIconIndex(row["Stype"].ToString())
};
nodeDict.Add(pid, node);
}
// 第二遍：建立父子关系
foreach (DataRow row in points.Rows)
{
int pid = Convert.ToInt32(row["Pid"]);
object parentObj = row["ParentId"];
if (parentObj != DBNull.Value)
{
int parentId = Convert.ToInt32(parentObj);
if (nodeDict.ContainsKey(parentId))
nodeDict[parentId].Nodes.Add(nodeDict[pid]);
}
else
{
treeview.Nodes.Add(nodeDict[pid]);
}
}
// 展开所有节点
treeview.ExpandAll();
// 添加节点选择事件
treeview.AfterSelect += (s, e) => DisplayPointDetails(e.Node);
}
catch (Exception ex)
{
MessageBox.Show($"加载树失败: {ex.Message}");
}
finally
{
treeview.EndUpdate();
}
}
private int GetNodeIconIndex(string v)
{
throw new NotImplementedException();
}
// 从数据库获取知识点
private DataTable GetKnowledgePoints()
{
using (SqlConnection conn = new SqlConnection(connectionString))
{
conn.Open();
string sql = @"SELECT
p.Pid,
p.Pname,
p.Stype,
p.Content,
r.ParentId
FROM pointnote p
LEFT JOIN KnowledgeRelations r ON p.Pid = r.ChildId";
using (var da = new SqlDataAdapter(sql, conn))
{
DataTable dt = new DataTable();
da.Fill(dt);
return dt;
}
}
}
private void label1_Click(object sender, EventArgs e)
{
}
// 显示选中知识点的详情
private void DisplayPointDetails(TreeNode node)
{
if (node?.Tag == null) return;
DataRow row = (DataRow)node.Tag;
txtName1.Text = row["Pname"].ToString();
txtSubject1.Text = row["Stype"].ToString();
txtContent1.Text = row["Content"].ToString();
}
private void SaveKnowledge(object sender, EventArgs e)
{
if (string.IsNullOrWhiteSpace(txtName.Text))
{
MessageBox.Show("知识点名称不能为空");
return;
}
using (SqlConnection conn = new SqlConnection(connectionString))
{
conn.Open();
string sql = @"INSERT INTO KnowledgeRelations (Pname, Stype, Content)
VALUES (@name, @subject, @content);
SELECT SCOPE_IDENTITY();";
using (var cmd = new SqlCommand(sql, conn))
{
cmd.Parameters.AddWithValue("@name", txtName1.Text);
cmd.Parameters.AddWithValue("@subject", txtSubject1.Text);
cmd.Parameters.AddWithValue("@content", txtContent1.Text);
try
{
int newId = Convert.ToInt32(cmd.ExecuteScalar());
MessageBox.Show($"保存成功! ID: {newId}");
LoadKnowledgeTree(); // 刷新树
}
catch (Exception ex)
{
MessageBox.Show($"保存失败: {ex.Message}");
}
}
}
}
}
}
错误：未将对象引用设置设置到对象的实例
最新发布
本文介绍了 SqlDataAdapter 的 Fill 方法中第二个参数的作用，即为填充到 DataSet 中的虚拟表指定名称，便于后期通过名称引用该表。
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