DataGridView定时刷新

新建DBHelper帮助其连接数据库

 1     public class Dbhelp
 2     {
 3         public static DataTable Query(string sqlConString)
 4         {
 5             DataTable dataTable = new DataTable();
 6             string sqlCmd = "select top 20 * from [Table_refresh testing] order by Id desc;";
 7             using (SqlConnection conn = new SqlConnection(sqlConString))
 8             {
 9                 conn.Open();
10                 SqlCommand sqlCommand = new SqlCommand(sqlCmd, conn);
11                 SqlDataReader sqlDataReader = sqlCommand.ExecuteReader();
12                 dataTable.Load(sqlDataReader);
13             }
14             return dataTable;
15         }
16     }

窗口Load事件处理器

        private void Form1_Load(object sender, EventArgs e)
        {
            CyclicRefreshing(); //启动DataGridView循环刷新任务                     
        }

CycliReferhing方法如下：

 1         private void CyclicRefreshing()
 2         {
 3             //开启一个任务线程
 4             Task task = Task.Run(async () =>
 5             {
 6                 while (!token.IsCancellationRequested)//触发token取消线程内部循环并且取消Task
 7                 {
 8                     resetEvent.WaitOne();//暂停线程
 9                     //此委托用于跨线程执行UI线程中的控件
10                     Action action = () =>
11                     {
12 
13                         DataTable dataTable = Dbhelp.Query(this.sqlConString);//执行查询
14                         this.guna2DataGridView1.DataSource = dataTable;
15                     };
16                     this.Invoke(action);//窗体执行委托
17                     await Task.Delay(2000);//间隔2s
18                 }
19             }, this.token);
20 
21         }

循环任务中的等待功能（ManualResetEvent）

        CancellationToken token;//声明变量
        resetEvent = new ManualResetEvent(true);//初始赋值为true为不暂停

暂停、取消暂停

1 resetEvent.Set();

2 resetEvent.Reset();

线程令牌声明，触发“取消”

1         CancellationTokenSource cancellationSource;
2         CancellationToken token;
3         cancellationSource = new CancellationTokenSource();//实例化
4         token = cancellationSource.Token;//获取令牌
5         cancellationSource.Cancel();//取消任务

导出Excel

使用EPPlus第三方库（商用收费），说明EPPlus不用于商业

1 ExcelPackage.LicenseContext = LicenseContext.NonCommercial;

实例化文件浏览器

1 FolderBrowserDialog folderBrowserDialog1 = new FolderBrowserDialog();

导出Excel代码如下：

 1         private void guna2ImageButton1_Click(object sender, EventArgs e)
 2         {
 3             ExcelPackage.LicenseContext = LicenseContext.NonCommercial;
 4             string CurrentPath;//Excel保存的路径完全限定名
 5             string excelPathStr;//文件浏览器选择的路径
 6             if (folderBrowserDialog1.ShowDialog() == DialogResult.OK)
 7             {
 8                 //判断选中路径是否为空
 9                 if (folderBrowserDialog1.SelectedPath != null)
10                 {
11                     excelPathStr = folderBrowserDialog1.SelectedPath.ToString();
12                     //得到的路径加上文件限定名（当前时间作为Excel名）
13                     CurrentPath = excelPathStr + $"\\{System.DateTime.Now.ToString("yyyy mm dd HH mm ss")}.xlsx";
14                     //创建一个Excel工作表并打开Excel包
15                     using (ExcelPackage package = new ExcelPackage(CurrentPath))
16                     {
17                         var sheet = package.Workbook.Worksheets.Add("TestSheet");//创建一个表单
18                         //加载DataGridView到Excel表单中
19                         sheet.Cells["A1"].LoadFromDataTable((DataTable)this.guna2DataGridView1.DataSource, true, TableStyles.Dark1);
20                         package.Save();
21                     }
22                     if (File.Exists(CurrentPath))//判断另存为的Excel是否导出成功
23                     {
24                         MessageBox.Show("表格导出成功", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
25                     }
26                     else
27                     {
28                         MessageBox.Show("表格导出失败", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
29                     }
30                 }
31             }
32         }

加载Json格式配置文件

声明Json映射类

 1     public class Initialize_Model
 2     {
 3         public string ConnectionString { get; set; }
 4 
 5         //如果为1加载初始化json，2加载保存json
 6         public int Status { get; set; }
 7         public int RefreshCycle { get; set; }
 8         public int DailyOutput { get; set; }
 9         public int MonthlyOutPut { get; set;}
10         public int QuarterlyOutPut { get; set; }
11     }

初始加载Json配置文件，并把加载的数据显示到相应的TextBox上：

 1         private void LoadConfigJson()
 2         {
 3 　　　　　　　　//Environment.CurrentDirectory获取应用程序所在文件夹
 4             initialize_Model = JsonConvert.DeserializeObject<Initialize_Model>(File.ReadAllText(Environment.CurrentDirectory + "\\Initialize.json"));//反序列化到对象类上
 5             this.guna2TextBox1.Text = initialize_Model.RefreshCycle.ToString();
 6             this.guna2TextBox2.Text = initialize_Model.DailyOutput.ToString();
 7             this.guna2TextBox3.Text = initialize_Model.MonthlyOutPut.ToString();
 8             this.guna2TextBox4.Text = initialize_Model.QuarterlyOutPut.ToString();
 9             sqlConString = initialize_Model.ConnectionString;
10         }

保存值到Json配置文件中：

1         private void SaveConfigJson()
2         {
3             initialize_Model.RefreshCycle = Convert.ToInt32(this.guna2TextBox1.Text.Trim());
4             initialize_Model.DailyOutput = Convert.ToInt32(this.guna2TextBox2.Text.Trim());
5             initialize_Model.MonthlyOutPut = Convert.ToInt32(this.guna2TextBox3.Text.Trim());
6             initialize_Model.QuarterlyOutPut = Convert.ToInt32(this.guna2TextBox4.Text.Trim());
7             initialize_Model.Status = 2;
8             File.WriteAllText(Environment.CurrentDirectory + "\\SaveConfig.json", JsonConvert.SerializeObject(initialize_Model, Formatting.Indented));
9         }