您应该将组的所有单选按钮放在相同的容器中，例如GroupBox或Panel。

无面板单选按钮

public class RadioButton2 : RadioButton
{
   public string GroupName { get; set; }
}

private void RadioButton2_Clicked(object sender, EventArgs e)
{
    RadioButton2 rb = (sender as RadioButton2);

    if (!rb.Checked)
    {
       foreach (var c in Controls)
       {
           if (c is RadioButton2 && (c as RadioButton2).GroupName == rb.GroupName)
           {
              (c as RadioButton2).Checked = false;
           }
       }

       rb.Checked = true;
    }
}

private void Form1_Load(object sender, EventArgs e)
{
    //a group
    RadioButton2 rb1 = new RadioButton2();
    rb1.Text = "radio1";
    rb1.AutoSize = true;
    rb1.AutoCheck = false;
    rb1.Top = 50;
    rb1.Left = 50;
    rb1.GroupName = "a";
    rb1.Click += RadioButton2_Clicked;
    Controls.Add(rb1);

    RadioButton2 rb2 = new RadioButton2();
    rb2.Text = "radio2";
    rb2.AutoSize = true;
    rb2.AutoCheck = false;
    rb2.Top = 50;
    rb2.Left = 100;
    rb2.GroupName = "a";
    rb2.Click += RadioButton2_Clicked;
    Controls.Add(rb2);

    //b group
    RadioButton2 rb3 = new RadioButton2();
    rb3.Text = "radio3";
    rb3.AutoSize = true;
    rb3.AutoCheck = false;
    rb3.Top = 80;
    rb3.Left = 50;
    rb3.GroupName = "b";
    rb3.Click += RadioButton2_Clicked;
    Controls.Add(rb3);

    RadioButton2 rb4 = new RadioButton2();
    rb4.Text = "radio4";
    rb4.AutoSize = true;
    rb4.AutoCheck = false;
    rb4.Top = 80;
    rb4.Left = 100;
    rb4.GroupName = "b";
    rb4.Click += RadioButton2_Clicked;
    Controls.Add(rb4);
}

如果你不能将它们放到一个容器中，那么你必须编写代码来改变每个RadioButton的checked状态:

private void rbDataSourceFile_CheckedChanged(object sender, EventArgs e)
{
    rbDataSourceNet.Checked = !rbDataSourceFile.Checked;
}

private void rbDataSourceNet_CheckedChanged(object sender, EventArgs e)
{
  rbDataSourceFile.Checked = !rbDataSourceNet.Checked;
}

看看把你的单选按钮放在一个GroupBox。

将单选按钮放入GroupBox(或其他面板)内

默认情况下，共享容器内的所有单选按钮都在同一个组中。 意思是，如果你选中了其中一个，其他的将不勾选。 如果您想要创建独立的单选按钮组，则必须将它们放置到不同的容器(如Group Box)中，或者通过后面的代码控制它们的Checked状态。