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！