To convert binary to string in c#, you can drag the textbox, label and button from your visual studio toolbox to your winform, then layout your UI as shown below.

Next, Create the BinaryToString method allow you to convert binary to text in c# as the following code.
public string BinaryToString(string data)
{
List<byte> bytes = new List<byte>();
for (int i = 0; i < data.Length; i += 8)
bytes.Add(Convert.ToByte(data.Substring(i, 8), 2));
return Encoding.ASCII.GetString(bytes.ToArray());
}
Finally, Add code to handle the Convert button click event.
private void btnConvert_Click(object sender, EventArgs e)
{
txtOutput.Text = BinaryToString(txtInput.Text);
}
Press F5 to build and run your project, then you can enter the binary code and convert binary to string in c#. In other words, you have created a binary to string converter in c# winforms.