有form1和form2两个窗口，form1有一个按钮，里面有一个string str="V1001",点击一下按钮，在form2的TextBox中显示出str的值。
public partial class Form1 : Form
    {
        public str;
        publicForm1()
        {
            InitializeComponent();
        }
 
        privatevoid button1_Click(objectsender, EventArgs e)
        {
            Form2 form2=new Form2();
            str="V1001";
            form2.Show();
        }
    }

  public partial class Form2 : Form  
       {      
            form1 fm=new form1();
            publicForm2()      
                 {            
                        InitializeComponent();      
                 }      
           privatevoid Form2_Load(objectsender, EventArgs e)      
                  {           
                          this.TextBox1.Text=fm.str;      
                   }


       }

1 public str; 这个是啥??? public string str;
2 publicForm1()
  {
    InitializeComponent();
  }
  你是故意把空格去掉的么
3 Form2窗体里面,你只是想要Form1窗体的引用,所以,form1 fm=new form1(); new一个新窗体是没有用的,反而占用资源.public Form1 fm = null; 这样就可以了
4 得把Form1传到Form2里面去,Form2才有东西可以用
 privatevoid button1_Click(objectsender, EventArgs e)
        {
            Form2 form2 = new Form2();
            form2.fm = this;
            str = "V1001";
            form2.Show();
        }

原来如此，问题解决了，谢了