Question

        double HP, L, hr, Est, eee, result;
        string output;
        HP = double.Parse(textBox1.Text);
        L = double.Parse(textBox2.Text);
        hr = double.Parse(textBox3.Text);
        Est = double.Parse(textBox4.Text);
        eee = double.Parse(textBox5.Text);

        result = HP * (L / 100) * 0.746 * hr * (((1 / Est) - (1 / eee)) * 100);
        output = " " + result;

        textBox6.Text = output;

我想在一个或多个文本框为空时显示验证消息。

Answer 1

确认字段不为空：

if(!String.IsNullOrEmpty(textBox.Text) && String.IsNullOrEmpty(...)){

}

检查值是否为有效的双倍：

double parsedValue;

if (!double.TryParse(textBox.Text, out parsedValue))
{
    MessageBox.Show("This is a double only field");
    return;
}

你会得到类似的东西：

if(nullorempty tests){
    if(youcanparse first textbox){
        the value of that textbox is not valid
    } else if(youcanparse second textbox){
         ...
    }
} else {
   show "you must enter something !"
}

等等

当texbox为空时显示验证错误

1 个答案: