C#教程之WinForm之BindingSource基础操作实例教程

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C#教程之WinForm之BindingSource基础操作实例教程

通常我们在进行数据绑定的时候，常用的数据源有DataSet、DataTable、BindingList<T>、还有强类型数据源。今天我们来通过实例了解一下BindingSource组建，分享给大家供大家参考借鉴之用。

BindingSource的两个用途：

（1）首先，它提供一个将窗体上的控件绑定到数据的间接层。这是通过将 BindingSource 组件绑定到数据源，然后将窗体上的控件绑定到 BindingSource 组件来完成的。与数据的所有进一步交互（包括导航、排序、筛选和更新）都是通过调用 BindingSource 组件来完成的。
（2）其次，BindingSource 组件可以充当强类型数据源。使用 Add 方法向 BindingSource 组件添加类型会创建一个该类型的列表。

一、对BindingSource的基础操作——增删改查

实例代码如下：

public partial class Form1 : Form

{

  //注当前DGV已经绑定到 ID 和 Name 列

  private BindingSource source = new BindingSource();

  public Form1()

  {

    InitializeComponent();

  }

  //窗体加载

  private void Form1_Load(object sender, EventArgs e)

  {

    this.source.DataSource = typeof(Custom);

    this.dataGridView1.DataSource = this.source;

  }

  //添加

  private void button1_Click(object sender, EventArgs e)

  {

    this.source.Add(new Custom(1,"A"));

    this.source.Add(new Custom(2,"B"));

  }

  //删除

  private void button2_Click(object sender, EventArgs e)

  {

    this.source.RemoveAt(0);

  }

  //排序 【有问题】

  private void button3_Click(object sender, EventArgs e)

  {

    this.source.Sort = "ID ASC";

    this.source.ResetBindings(false);

  }

  //筛选 【有问题】

  private void button4_Click(object sender, EventArgs e)

  {

    this.source.Filter = "ID = 1";

    this.source.ResetBindings(false);

  }

  //向下移动

  private void button5_Click(object sender, EventArgs e)

  {

    this.source.MoveNext();

    MessageBox.Show(this.source.Position.ToString());

  }

  //向上移动

  private void button9_Click(object sender, EventArgs e)

  {

    this.source.MovePrevious();

    MessageBox.Show(this.source.Position.ToString());

  }

  //获取当前项

  private void button6_Click(object sender, EventArgs e)

  {

    Custom custom = (Custom)this.source.Current;

    MessageBox.Show(" 所处的位置 : " + this.source.IndexOf(custom).ToString());

    MessageBox.Show("custom.Name : " + custom.Name);

  }

  //修改当前项

  private void button7_Click(object sender, EventArgs e)

  {

    Custom custom = (Custom)this.source.Current;

    custom.Name = "修改后的值";

    this.source.ResetCurrentItem();

  }

  //删除当前项

  private void button8_Click(object sender, EventArgs e)

  {

    Custom custom = (Custom)this.source.Current;

    this.source.Remove(custom);

  }

}

//自定义类 字段必须属性公开化

public class Custom

{

  public Custom()

  { }

  public Custom(int ID, string Name)

  {

    this.ID = ID;

    this.Name = Name;

  }

  private int id;

  public int ID

  {

    get { return id; }

    set { id = value; }

  }

  private string name;

  public string Name

  {

    get { return name; }

    set { name = value; }

  }

}

二、下面的示例演示如何在两种不同情况下绑定 DBNull 值。

第一种情况演示如何设置字符串属性的 NullValue；第二种情况演示如何设置图像属性的 NullValue。

下面的示例演示如何在两种不同情况下绑定 DBNull 值。第一种情况演示如何设置字符串属性的 NullValue；第二种情况演示如何设置图像属性的 NullValue。

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Text;

using System.Data.SqlClient;

using System.Windows.Forms;

namespace DBNullCS

{

  public class Form1 : Form

  {

    public Form1()

    {    

      this.Load += new EventHandler(Form1_Load);

    }

    // The controls and components we need for the form.

    private Button button1;

    private PictureBox pictureBox1;

    private BindingSource bindingSource1;

    private TextBox textBox1;

    private TextBox textBox2;

    // Data table to hold the database data.

    DataTable employeeTable = new DataTable();

    void Form1_Load(object sender, EventArgs e)

    {

      // Basic form setup.

      this.pictureBox1 = new PictureBox();

      this.bindingSource1 = new BindingSource();

      this.textBox1 = new TextBox();

      this.textBox2 = new TextBox();

      this.button1 = new Button();

      this.pictureBox1.Location = new System.Drawing.Point(20, 20);

      this.pictureBox1.Size = new System.Drawing.Size(174, 179);

      this.textBox1.Location = new System.Drawing.Point(25, 215);

      this.textBox1.ReadOnly = true;

      this.textBox2.Location = new System.Drawing.Point(25, 241);

      this.textBox2.ReadOnly = true;

      this.button1.Location = new System.Drawing.Point(200, 103);

      this.button1.Text = "Move Next";

      this.button1.Click += new System.EventHandler(this.button1_Click);

      this.ClientSize = new System.Drawing.Size(292, 273);

      this.Controls.Add(this.button1);

      this.Controls.Add(this.textBox2);

      this.Controls.Add(this.textBox1);

      this.Controls.Add(this.pictureBox1);

      this.ResumeLayout(false);

      this.PerformLayout();

      // Create the connection string and populate the data table

      // with data.

      string connectionString = "Integrated Security=SSPI;" +

        "Persist Security Info = False;Initial Catalog=Northwind;" +

        "Data Source = localhost";

      SqlConnection connection = new SqlConnection();

      connection.ConnectionString = connectionString;

      SqlDataAdapter employeeAdapter = 

        new SqlDataAdapter(new SqlCommand("Select * from Employees", connection));

      connection.Open();

      employeeAdapter.Fill(employeeTable);

      // Set the DataSource property of the BindingSource to the employee table.

      bindingSource1.DataSource = employeeTable;

      // Set up the binding to the ReportsTo column.

      Binding reportsToBinding = textBox2.DataBindings.Add("Text", bindingSource1, 

        "ReportsTo", true);

      // Set the NullValue property for this binding.

      reportsToBinding.NullValue = "No Manager";

      // Set up the binding for the PictureBox using the Add method, setting

      // the null value in method call.

      pictureBox1.DataBindings.Add("Image", bindingSource1, "Photo", true, 

        DataSourceUpdateMode.Never, new Bitmap(typeof(Button), "Button.bmp"));

      // Set up the remaining binding.

      textBox1.DataBindings.Add("Text", bindingSource1, "LastName", true);

    }

    // Move through the data when the button is clicked.

    private void button1_Click(object sender, EventArgs e)

    {

      bindingSource1.MoveNext();

    }

    [STAThread]

    static void Main()

    {

      Application.EnableVisualStyles();

      Application.Run(new Form1());

    }

  }

}

希望本文实例对大家C#程序设计的学习有所帮助！

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