C# 子窗体中调用父窗体中的方法(或多窗体之间方法调用)

C# Code:

//父窗体是是frmParent，子窗体是frmChildA
//在父窗体中打开子窗体
frmChildA child = new frmChildA();
child.MdiParent = this;
child.Show();


//子窗体调父窗体方法：
//错误的调用!!!!!!!!
(this.MdiParent as frmParent).ParentFoo();

//来源:C/S框架网(www.csframework.com) QQ:1980854898

C# Code:

///<summary>
/// 主窗体接口
///</summary>
public interface IMdiParent
{
   void ParentFoo();
}


///<summary>
/// 子窗体接口
///</summary>
public interface IMyChildForm
{
   void Foo();
}

C# Code:

///<summary>
/// 主窗体，实现IMdiParent接口
///</summary>
public partial class frmParent : Form, IMdiParent
{
   public frmParent()
   {
      InitializeComponent();
   }
  
   private void form1ToolStripMenuItem_Click( object sender, EventArgs e)
   {
      //打开子窗体
      frmChildA child = new frmChildA();
      child.MdiParent = this;
      child.Show();
   }
  
   private void menuCallFoo_Click( object sender, EventArgs e)
   {
      //调用子窗体的Foo()方法
      Form activedChild = this.ActiveMdiChild;
      if ((activedChild != null) && (activedChild is IMyChildForm))
         (activedChild as IMyChildForm).Foo();
   }
  
   #region IMdiParent 成员
  
   public void ParentFoo()
   {
      MessageBox.Show("调用" this.GetType().FullName ".ParentFoo()方法！");
   }
  
   #endregion
}

//来源:C/S框架网(www.csframework.com) QQ:1980854898

C# Code:

///<summary>
/// 子窗体，实现IMyChildForm接口
///</summary>
public partial class frmChildA : Form, IMyChildForm
{
   public frmChildA()
   {
      InitializeComponent();
   }
  
   #region IMyChildForm 成员
  
   public void Foo()
   {
      MessageBox.Show("调用" this.GetType().FullName ".Foo()方法！");
   }
  
   #endregion
  
   private void btnParentFoo_Click( object sender, EventArgs e)
   {
      //调用父窗体的ParentFoo()方法
      if (( this.MdiParent != null) && ( this.MdiParent is IMdiParent))
      ( this.MdiParent as IMdiParent).ParentFoo();
   }
  
   private void btnErrCall_Click( object sender, EventArgs e)
   {
      //错误的调用
      ( this.MdiParent as frmParent).ParentFoo();
   }
  
   //来源:C/S框架网(www.csframework.com) QQ:1980854898