DataTable.Compute自由计算表达式

public static object Eval(string AExpression)
{
    try
    {
        return new System.Data.DataTable().Compute(AExpression, "");
    }
    catch
    {
        return null;
    }
}

private void button1_Click(object sender, EventArgs e)
{
    lblResult.Text = Eval("(1.5+2.5)*2/4").ToString();
}