Question

private void button1_Click(object sender, EventArgs e)
{
    t = new Thread(new ParameterizedThreadStart(startRequest));
    t.Start(textBox1);
}

void startRequest(object textBox1)
{
    textBox1.Text = "hello";
}

here I get an error that textBox1 doesn’t have a property Text, in the main thread its all okay, but in the new thread I get an error ,how to fix this?

Answer 1

You must cast your object to Type TextBox before using its Text property.

void startRequest(object textBox1)
{
    MethodInvoker mi = delegate
    {
        TextBox tempTextBox = textBox1 as TextBox;
        if (tempTextBox != null)
            tempTextBox.Text = "hello";
    };

    if (this.InvokeRequired)
        this.Invoke(mi);
}

Its also better to check for null, if the casting fails.