using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace WindowsFormsApp1
{
public partial class Form1 : Form
{
private SQLiteConnection connection;
private const string dbFile = "knowledge.db";
public Form1()
{
InitializeComponent();
InitializeDatabase();
LoadSubjects();
}
// 初始化数据库
private void InitializeDatabase()
{
if (!File.Exists(dbFile))
{
SQLiteConnection.CreateFile(dbFile);
}
connection = new SQLiteConnection($"Data Source={dbFile};Version=3;");
connection.Open();
// 创建学科表
string subjectSql = @"CREATE TABLE IF NOT EXISTS Subjects (
Id INTEGER PRIMARY KEY AUTOINCREMENT,
Name TEXT NOT NULL UNIQUE)";
// 创建知识点表
string knowledgeSql = @"CREATE TABLE IF NOT EXISTS KnowledgePoints (
Id INTEGER PRIMARY KEY AUTOINCREMENT,
SubjectId INTEGER NOT NULL,
Title TEXT NOT NULL,
Description TEXT,
Image BLOB,
FOREIGN KEY(SubjectId) REFERENCES Subjects(Id))";
ExecuteNonQuery(subjectSql);
ExecuteNonQuery(knowledgeSql);
}
private void ExecuteNonQuery(string sql)
{
using (var cmd = new SQLiteCommand(sql, connection))
{
cmd.ExecuteNonQuery();
}
}
// 加载所有学科
private void LoadSubjects()
{
cmbSubjects.Items.Clear();
string sql = "SELECT Id, Name FROM Subjects";
using (var cmd = new SQLiteCommand(sql, connection))
using (var reader = cmd.ExecuteReader())
{
while (reader.Read())
{
cmbSubjects.Items.Add(new Subject(
reader.GetInt32(0),
reader.GetString(1)
));
}
}
}
private void 添加新学科ToolStripMenuItem_Click(object sender, EventArgs e)
{
string subjectName = txtNewSubject.Text.Trim();
if (string.IsNullOrEmpty(subjectName))
{
MessageBox.Show("请输入学科名称");
return;
}
string sql = "INSERT INTO Subjects (Name) VALUES (@name)";
using (var cmd = new SQLiteCommand(sql, connection))
{
cmd.Parameters.AddWithValue("@name", subjectName);
cmd.ExecuteNonQuery();
}
txtNewSubject.Clear();
LoadSubjects();
MessageBox.Show("学科添加成功！");
}
private void 添加知识点ToolStripMenuItem_Click(object sender, EventArgs e)
{
if (cmbSubjects.SelectedItem == null)
{
MessageBox.Show("请先选择学科");
return;
}
var subject = (Subject)cmbSubjects.SelectedItem;
string title = txtTitle.Text.Trim();
string description = txtDescription.Text;
if (string.IsNullOrEmpty(title))
{
MessageBox.Show("请输入知识点标题");
return;
}
// 处理
图片
byte[] imageBytes = null;
if (picImage.Image != null)
{
using (var ms = new MemoryStream())
{
picImage.Image.Save(ms, picImage.Image.RawFormat);
imageBytes = ms.ToArray();
}
}
// 插入数据库
string sql = @"INSERT INTO KnowledgePoints
(SubjectId, Title, Description, Image)
VALUES (@subjectId, @title, @desc, @image)";
using (var cmd = new SQLiteCommand(sql, connection))
{
cmd.Parameters.AddWithValue("@subjectId", subject.Id);
cmd.Parameters.AddWithValue("@title", title);
cmd.Parameters.AddWithValue("@desc", description);
cmd.Parameters.AddWithValue("@image", imageBytes ?? (object)DBNull.Value);
cmd.ExecuteNonQuery();
}
ClearKnowledgeForm();
MessageBox.Show("知识点添加成功！");
}
private void
上传图片ToolStripMenuItem_Click(object sender, EventArgs e)
{
using (OpenFileDialog dlg = new OpenFileDialog())
{
dlg.Filter = "
图片文件|*.jpg;*.jpeg;*.png;*.bmp";
if (dlg.ShowDialog() == DialogResult.OK)
{
picImage.Image = new Bitmap(dlg.FileName);
}
}
}
private void ClearKnowledgeForm()
{
txtTitle.Clear();
txtDescription.Clear();
picImage.Image = null;
}
private void 查看知识点ToolStripMenuItem_Click(object sender, EventArgs e)
{
var
viewForm = new Knowledge
Viewer(connection);
viewForm.ShowDialog();
}
}
public class Subject
{
public int Id { get; }
public string Name { get; }
public Subject(int id, string name)
{
Id = id;
Name = name;
}
public override string ToString() => Name;
}
}using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace Knowledge
Viewer
{
public partial class Form1 : Form
{
private
TreeView treeView;
private WebBrowser browser;
private SQLiteConnection connection;
public Knowledge
Viewer(SQLiteConnection conn)
{
connection = conn;
InitializeUI();
LoadData();
}
private void InitializeUI()
{
this.Size = new Size(800, 600);
this.Text = "知识点浏览器";
SplitContainer split = new SplitContainer();
split.Dock = DockStyle.Fill;
split.SplitterDistance = 200;
treeView = new
TreeView();
treeView.Dock = DockStyle.Fill;
treeView.AfterSelect +=
TreeView_AfterSelect;
browser = new WebBrowser();
browser.Dock = DockStyle.Fill;
split.Panel1.Controls.Add(
treeView);
split.Panel2.Controls.Add(browser);
this.Controls.Add(split);
}
private void LoadData()
{
// 加载学科
string subjectSql = "SELECT Id, Name FROM Subjects";
using (var cmd = new SQLiteCommand(subjectSql, connection))
using (var reader = cmd.ExecuteReader())
{
while (reader.Read())
{
var subjectNode = new TreeNode(reader.GetString(1))
{
Tag = $"Subject_{reader.GetInt32(0)}"
};
treeView.Nodes.Add(subjectNode);
LoadKnowledgePoints(subjectNode, reader.GetInt32(0));
}
}
}
private void LoadKnowledgePoints(TreeNode parentNode, int subjectId)
{
string sql = "SELECT Id, Title FROM KnowledgePoints WHERE SubjectId = @subjectId";
using (var cmd = new SQLiteCommand(sql, connection))
{
cmd.Parameters.AddWithValue("@subjectId", subjectId);
using (var reader = cmd.ExecuteReader())
{
while (reader.Read())
{
var pointNode = new TreeNode(reader.GetString(1))
{
Tag = $"Point_{reader.GetInt32(0)}"
};
parentNode.Nodes.Add(pointNode);
}
}
}
}
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
}
private void
treeView1_AfterSelect(object sender,
TreeViewEventArgs e)
{
if (e.Node.Tag == null) return;
var parts = e.Node.Tag.ToString().Split('_');
if (parts[0] == "Point")
{
int pointId = int.Parse(parts[1]);
DisplayKnowledgePoint(pointId);
}
}
private void DisplayKnowledgePoint(int pointId)
{
string sql = "SELECT Title, Description, Image FROM KnowledgePoints WHERE Id = @id";
using (var cmd = new SQLiteCommand(sql, connection))
{
cmd.Parameters.AddWithValue("@id", pointId);
using (var reader = cmd.ExecuteReader())
{
if (reader.Read())
{
string title = reader.GetString(0);
string description = reader.GetString(1);
byte[] imageBytes = reader.IsDBNull(2) ? null : (byte[])reader[2];
string html = $"<h1>{title}</h1><p>{description.Replace("\n", "<br>")}</p>";
if (imageBytes != null)
{
string base64 = Convert.ToBase64String(imageBytes);
html += $"<img src='data:image/png;base64,{base64}' style='max-width:100%'/>";
}
browser.DocumentText = html;
}
}
}
}
}
怎么改
本文介绍了一种简化TreeView中图片显示的方法，通过直接在主目录下放置图片，并设置CollapseImageUrl、ExpandImageUrl及NoExpandImageUrl属性来实现节点图像的快速配置。
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