C#如何设置另一窗口控件属性？

LZ是不是这个意思 比如说 在b窗体设置a窗体控件的属性.
如果是这个意思的话,你在b窗体加一个有参的构造方法,参数是窗体对象,a窗体new b窗体时,把自己传过去即可.

public partial class Form1 : Form
{
Label l1;
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
l1 = this.label1;
}
private void button1_Click(object sender, EventArgs e)
{
Form2 f2 = new Form2(l1);
f2.ShowDialog();
}
}

public partial class Form2 : Form
{
Label l;
public Form2()
{
InitializeComponent();
}
public Form2(Label label)
{
InitializeComponent();
this.l = label;
}
private void button1_Click(object sender, EventArgs e)
{
l.Text = this.textBox1.Text;
this.Close();
}
}