C#中DataBindings用法實例分析

2020-01-24 01:07:32

字體：大中小

來源：轉載

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本文實例講述了C#中DataBindings用法。分享給大家供大家參考，具體如下：

在C#操作數據庫過程中，針對一般的文本控件，比如TextBox，Label等，我們賦值直接使用類似TextBox.Text=****的方式來進行，這種方式從某種意義上來說的確是最簡便的方式，但是對于復雜一些的空間，比如說DataGridView，這個時候，綁定數據源我們一般使用DataGridView1.DataSource=****的方式來進行，如果數據源稍微有更改，那么只需要重新調用綁定一遍即可?？梢哉f這種方式是單向的，也即從數據庫到UI，但是有沒有一種方式能夠實現數據源改變的時候，不用重新綁定DataGridView就讓它能夠自動刷新數據呢，當然，這里要提到的就是DataBinding了。

代碼如下

Form2.cs代碼：

using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Linq;using System.Text;using System.Windows.Forms;namespace DataBindingsTest{  public partial class Form2 : Form  {    public Form2()    {      InitializeComponent();    }    MyDataSource mydatasource = new MyDataSource(); //應用于第二種方式    public int Num { get; set; } //應用于第三種方式    public List<BlogNew> blogNews { get; set; } //應用于第四種方式    public BindingList<BlogNew> blogNewsRegardUI { get; set; } //應用于DataGridView界面UI更新     private void mainFrm_Load(object sender, EventArgs e)    {      #region 測試一      /************************************************       * 第一個值：要綁定到TextBox的什么地方       * 第二個值：數據源是什么       * 第三個值：應該取數據源的什么屬性       * 第四個值：是否開啟數據格式化       * 第五個值：在什么時候啟用數據源綁定       * *********************************************/      textBox1.DataBindings.Add("Text", trackBar1, "Value", false, DataSourceUpdateMode.OnPropertyChanged);      #endregion      #region 測試二      /*********************************************       * 這個主要就是通過一個外部的類，當做數據源       * *********************************************/      mydatasource.Myvalue = "這是個測試";      textBox2.DataBindings.Add("Text", mydatasource, "Myvalue", false, DataSourceUpdateMode.OnPropertyChanged);      #endregion      #region 測試三      /*****************************************       *這個主要就是通過本身擁有的屬性，當做數據源       ****************************************/      Num = 5;      textBox3.DataBindings.Add("Text", this, "Num", false, DataSourceUpdateMode.OnPropertyChanged);      #endregion      /*       * 注意：上面的3個測試，改變文本框中的值，數據源中對應的屬性值會改變         *    但是，數據源的屬性值改變了，文本框中的值不會改變       */      #region 測試四 ： List<T>      blogNews = new List<BlogNew>();      blogNews.Add(new BlogNew { BlogID = 1, BlogTitle = "人生若只如初見" });      blogNews.Add(new BlogNew { BlogID = 2, BlogTitle = "何事秋風悲畫扇" });      blogNews.Add(new BlogNew { BlogID = 3, BlogTitle = "最喜歡納蘭性德" });      dataGridView1.DataBindings.Add("DataSource", this, "blogNews", false, DataSourceUpdateMode.OnPropertyChanged);      #endregion      #region 測試五 ： BindingList<T>      blogNewsRegardUI = new BindingList<BlogNew>();      blogNewsRegardUI.Add(new BlogNew { BlogID = 11, BlogTitle = "僵臥孤村不自哀" });      blogNewsRegardUI.Add(new BlogNew { BlogID = 12, BlogTitle = "尚思為國戍輪臺" });      blogNewsRegardUI.Add(new BlogNew { BlogID = 13, BlogTitle = "夜闌臥聽風吹雨" });      dataGridView2.DataBindings.Add("DataSource", this, "blogNewsRegardUI", false, DataSourceUpdateMode.OnPropertyChanged);      #endregion    }    private void button1_Click(object sender, EventArgs e)    {      //從這里可以看出，改變了TextBox2中的值，這里的值也改變了，原因是因為類屬于引用類型      MessageBox.Show(mydatasource.Myvalue);    }    private void button2_Click(object sender, EventArgs e)    {      //從這里可以看出，改變了TextBox3中的值，這里的值也改變了，      //原因是Num被當做了當前窗體的一個屬性(窗體本身就是一個類)，也屬于引用類型      MessageBox.Show(Num.ToString());      //this.Num = 10;      //MessageBox.Show(Num.ToString());    }    private void button3_Click(object sender, EventArgs e)    {      //在這里向DataGridView中插入一行      var data = dataGridView1.DataSource as List<BlogNew>;      data.Add(new BlogNew { BlogID = 4, BlogTitle = "取次花叢懶回顧，半緣修道半緣君" });      foreach (BlogNew blogNew in dataGridView1.DataSource as List<BlogNew>)      {        /***********         * 當我們心插入一條BlogID記錄為4的數據的時候，在界面上可以看出dataGridView1的dataSource已經被更新，         * 但是界面上依舊顯示為BlogID為1,2,3三條數據，很奇怪         * *********************/        MessageBox.Show(blogNew.BlogID + "--" + blogNew.BlogTitle);      }    }    private void button4_Click(object sender, EventArgs e)    {      /*這里主要用來解決DataGridView1界面不更新的問題，其實原因在于使用了List<BlogNew>,這里我們采用BindList<BlogNew>       *通過測試，我們發現，只要數據源改變，界面就可以自動的進行更新了，很是方便，不需要重新綁定       */      var dataRegardUI = dataGridView2.DataSource as BindingList<BlogNew>;      dataRegardUI.Add(new BlogNew { BlogID = 20, BlogTitle = "竹外桃花三兩枝，春江水暖鴨先知" });    }  }  public class MyDataSource  {    public string Myvalue { get; set; }  }  public class BlogNew  {    public int BlogID { get; set; }    public string BlogTitle { get; set; }  }}

Form2.Designer.cs代碼：

namespace DataBindingsTest{  partial class Form2  {    /// <summary>    /// Required designer variable.    /// </summary>    private System.ComponentModel.IContainer components = null;    /// <summary>    /// Clean up any resources being used.    /// </summary>    /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>    protected override void Dispose(bool disposing)    {      if (disposing && (components != null))      {        components.Dispose();      }      base.Dispose(disposing);    }    #region Windows Form Designer generated code    /// <summary>    /// Required method for Designer support - do not modify    /// the contents of this method with the code editor.    /// </summary>    private void InitializeComponent()    {      this.groupBox1 = new System.Windows.Forms.GroupBox();      this.groupBox2 = new System.Windows.Forms.GroupBox();      this.button1 = new System.Windows.Forms.Button();      this.textBox2 = new System.Windows.Forms.TextBox();      this.groupBox3 = new System.Windows.Forms.GroupBox();      this.button2 = new System.Windows.Forms.Button();      this.textBox3 = new System.Windows.Forms.TextBox();      this.groupBox4 = new System.Windows.Forms.GroupBox();      this.button3 = new System.Windows.Forms.Button();      this.dataGridView1 = new System.Windows.Forms.DataGridView();      this.groupBox5 = new System.Windows.Forms.GroupBox();      this.button4 = new System.Windows.Forms.Button();      this.dataGridView2 = new System.Windows.Forms.DataGridView();      this.textBox1 = new System.Windows.Forms.TextBox();      this.trackBar1 = new System.Windows.Forms.TrackBar();      this.groupBox1.SuspendLayout();      this.groupBox2.SuspendLayout();      this.groupBox3.SuspendLayout();      this.groupBox4.SuspendLayout();      ((System.ComponentModel.ISupportInitialize)(this.dataGridView1)).BeginInit();      this.groupBox5.SuspendLayout();      ((System.ComponentModel.ISupportInitialize)(this.dataGridView2)).BeginInit();      ((System.ComponentModel.ISupportInitialize)(this.trackBar1)).BeginInit();      this.SuspendLayout();      //       // groupBox1      //       this.groupBox1.Controls.Add(this.trackBar1);      this.groupBox1.Controls.Add(this.textBox1);      this.groupBox1.Location = new System.Drawing.Point(12, 12);      this.groupBox1.Name = "groupBox1";      this.groupBox1.Size = new System.Drawing.Size(200, 100);      this.groupBox1.TabIndex = 0;      this.groupBox1.TabStop = false;      this.groupBox1.Text = "方式一";      //       // groupBox2      //       this.groupBox2.Controls.Add(this.button1);      this.groupBox2.Controls.Add(this.textBox2);      this.groupBox2.Location = new System.Drawing.Point(218, 12);      this.groupBox2.Name = "groupBox2";      this.groupBox2.Size = new System.Drawing.Size(200, 100);      this.groupBox2.TabIndex = 2;      this.groupBox2.TabStop = false;      this.groupBox2.Text = "方式二";      //       // button1      //       this.button1.Location = new System.Drawing.Point(22, 59);      this.button1.Name = "button1";      this.button1.Size = new System.Drawing.Size(157, 23);      this.button1.TabIndex = 3;      this.button1.Text = "查看已修改的數據源的值";      this.button1.UseVisualStyleBackColor = true;      this.button1.Click += new System.EventHandler(this.button1_Click);      //       // textBox2      //       this.textBox2.Location = new System.Drawing.Point(22, 20);      this.textBox2.Name = "textBox2";      this.textBox2.Size = new System.Drawing.Size(157, 21);      this.textBox2.TabIndex = 2;      //       // groupBox3      //       this.groupBox3.Controls.Add(this.button2);      this.groupBox3.Controls.Add(this.textBox3);      this.groupBox3.Location = new System.Drawing.Point(428, 12);      this.groupBox3.Name = "groupBox3";      this.groupBox3.Size = new System.Drawing.Size(200, 100);      this.groupBox3.TabIndex = 4;      this.groupBox3.TabStop = false;      this.groupBox3.Text = "方式三";      //       // button2      //       this.button2.Location = new System.Drawing.Point(22, 59);      this.button2.Name = "button2";      this.button2.Size = new System.Drawing.Size(157, 23);      this.button2.TabIndex = 3;      this.button2.Text = "查看已修改的數據源的值";      this.button2.UseVisualStyleBackColor = true;      this.button2.Click += new System.EventHandler(this.button2_Click);      //       // textBox3      //       this.textBox3.Location = new System.Drawing.Point(22, 20);      this.textBox3.Name = "textBox3";      this.textBox3.Size = new System.Drawing.Size(157, 21);      this.textBox3.TabIndex = 2;      //       // groupBox4      //       this.groupBox4.Controls.Add(this.button3);      this.groupBox4.Controls.Add(this.dataGridView1);      this.groupBox4.Location = new System.Drawing.Point(12, 118);      this.groupBox4.Name = "groupBox4";      this.groupBox4.Size = new System.Drawing.Size(568, 157);      this.groupBox4.TabIndex = 5;      this.groupBox4.TabStop = false;      this.groupBox4.Text = "方式四";      //       // button3      //       this.button3.Location = new System.Drawing.Point(377, 122);      this.button3.Name = "button3";      this.button3.Size = new System.Drawing.Size(157, 23);      this.button3.TabIndex = 4;      this.button3.Text = "插入一行";      this.button3.UseVisualStyleBackColor = true;      this.button3.Click += new System.EventHandler(this.button3_Click);      //       // dataGridView1      //       this.dataGridView1.ColumnHeadersHeightSizeMode = System.Windows.Forms.DataGridViewColumnHeadersHeightSizeMode.AutoSize;      this.dataGridView1.Location = new System.Drawing.Point(18, 20);      this.dataGridView1.Name = "dataGridView1";      this.dataGridView1.RowTemplate.Height = 23;      this.dataGridView1.Size = new System.Drawing.Size(516, 96);      this.dataGridView1.TabIndex = 0;      //       // groupBox5      //       this.groupBox5.Controls.Add(this.button4);      this.groupBox5.Controls.Add(this.dataGridView2);      this.groupBox5.Location = new System.Drawing.Point(12, 281);      this.groupBox5.Name = "groupBox5";      this.groupBox5.Size = new System.Drawing.Size(568, 162);      this.groupBox5.TabIndex = 6;      this.groupBox5.TabStop = false;      this.groupBox5.Text = "方式五";      //       // button4      //       this.button4.Location = new System.Drawing.Point(377, 127);      this.button4.Name = "button4";      this.button4.Size = new System.Drawing.Size(157, 23);      this.button4.TabIndex = 4;      this.button4.Text = "插入一行";      this.button4.UseVisualStyleBackColor = true;      this.button4.Click += new System.EventHandler(this.button4_Click);      //       // dataGridView2      //       this.dataGridView2.ColumnHeadersHeightSizeMode = System.Windows.Forms.DataGridViewColumnHeadersHeightSizeMode.AutoSize;      this.dataGridView2.Location = new System.Drawing.Point(18, 20);      this.dataGridView2.Name = "dataGridView2";      this.dataGridView2.RowTemplate.Height = 23;      this.dataGridView2.Size = new System.Drawing.Size(516, 91);      this.dataGridView2.TabIndex = 0;      //       // textBox1      //       this.textBox1.Location = new System.Drawing.Point(18, 20);      this.textBox1.Name = "textBox1";      this.textBox1.Size = new System.Drawing.Size(157, 21);      this.textBox1.TabIndex = 0;      //       // trackBar1      //       this.trackBar1.Location = new System.Drawing.Point(18, 47);      this.trackBar1.Name = "trackBar1";      this.trackBar1.Size = new System.Drawing.Size(157, 45);      this.trackBar1.TabIndex = 1;      //       // Form2      //       this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 12F);      this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;      this.ClientSize = new System.Drawing.Size(676, 471);      this.Controls.Add(this.groupBox5);      this.Controls.Add(this.groupBox4);      this.Controls.Add(this.groupBox3);      this.Controls.Add(this.groupBox2);      this.Controls.Add(this.groupBox1);      this.Name = "Form2";      this.Text = "Form2";      this.Load += new System.EventHandler(this.mainFrm_Load);      this.groupBox1.ResumeLayout(false);      this.groupBox1.PerformLayout();      this.groupBox2.ResumeLayout(false);      this.groupBox2.PerformLayout();      this.groupBox3.ResumeLayout(false);      this.groupBox3.PerformLayout();      this.groupBox4.ResumeLayout(false);      ((System.ComponentModel.ISupportInitialize)(this.dataGridView1)).EndInit();      this.groupBox5.ResumeLayout(false);      ((System.ComponentModel.ISupportInitialize)(this.dataGridView2)).EndInit();      ((System.ComponentModel.ISupportInitialize)(this.trackBar1)).EndInit();      this.ResumeLayout(false);    }    #endregion    private System.Windows.Forms.GroupBox groupBox1;    private System.Windows.Forms.GroupBox groupBox2;    private System.Windows.Forms.Button button1;    private System.Windows.Forms.TextBox textBox2;    private System.Windows.Forms.GroupBox groupBox3;    private System.Windows.Forms.Button button2;    private System.Windows.Forms.TextBox textBox3;    private System.Windows.Forms.GroupBox groupBox4;    private System.Windows.Forms.Button button3;    private System.Windows.Forms.DataGridView dataGridView1;    private System.Windows.Forms.GroupBox groupBox5;    private System.Windows.Forms.Button button4;    private System.Windows.Forms.DataGridView dataGridView2;    private System.Windows.Forms.TrackBar trackBar1;    private System.Windows.Forms.TextBox textBox1;  }}

效果圖：