当我尝试将字体颜色设置为黄色时，我搞砸了我的代码。请帮忙!!
说明： 创建一个包含两个文本框和两个按钮的Windows应用程序。文本框应该用于允许用户输入两个正数值。按钮应标记为Add and Multiply。创建事件处理程序方法，以检索值，执行计算并在标签上显示计算结果。结果标签最初应设置为不可见，字体颜色为黄色。如果输入了无效数据，请在结果标签上将字体颜色更改为红色并显示消息＆＃34;值必须为数字且＆gt; 0。＆＃34;显示最终答案时，字体颜色应为黄色。文本框标题将需要其他标签。不允许输入非数字字符。调用 TryParse（）方法来检索值。应该命名程序语句中涉及的所有控件。右对齐文本框中的值。
这是我在form1页面上得到的内容
namespace Add_and_Multiply
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
int val1;
int val2;
val1 = Convert.ToInt32(textBox1.Text);
val2 = Convert.ToInt32(textBox2.Text);
label3.Text = Convert.ToString(val1 + val2); //after this line I tried putting the code to give me yellow color text and now I have so many errors:(
}
private void button2_Click(object sender, EventArgs e)
{
int val1;
int val2;
val1 = Convert.ToInt32(textBox1.Text);
val2 = Convert.ToInt32(textBox2.Text);
label3.Text = Convert.ToString(val1 * val2);
}
private void Form1_Load(object sender, EventArgs e)
{
}
}
}
有人可以帮助我吗？我在这方面不太好。 感谢
有人告诉我这样解决。
namespace Add_and_Multiply
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
int val1;
int val2;
if(!int.TryParse(textBox1.Text.Trim(), out val1))
{
lblYellow.ForeColor = Color.Yellow;
lblYellow.Visible = true;
lblYellow.Text = "First value is invalid";
return;
}
if(!int.TryParse(textBox2.Text.Trim(), out val2))
{
lblYellow.ForeColor = Color.Yellow;
lblYellow.Visible = true;
lblYellow.Text = "Second value is invalid";
return;
}
lblYellow.Visible = false;
label3.Text = Convert.ToString(val1 + val2);
}
private void button2_Click(object sender, EventArgs e)
{
int val1;
int val2;
if(!int.TryParse(textBox1.Text.Trim(), out val1))
{
lblYellow.ForeColor = Color.Yellow;
lblYellow.Visible = true;
lblYellow.Text = "First value is invalid";
return;
}
if(!int.TryParse(textBox2.Text.Trim(), out val2))
{
lblYellow.ForeColor = Color.Yellow;
lblYellow.Visible = true;
lblYellow.Text = "Second value is invalid";
return;
}
lblYellow.Visible = false;
label3.Text = Convert.ToString(val1 * val2);
}
private void Form1_Load(object sender, EventArgs e)
{
}
}
}
但我收到错误＆＃34;名称＆＃39; lblYellow＆＃39;在目前的背景下不存在剂量Form1.cs＆＃34;我应该在private void button1_click line之前声明它吗？
答案 0 :(得分：0)
label3.ForeColor = Color.Yellow;
...应将标签颜色更改为黄色......
但是你有另一个问题。您没有检查无效输入以将标签更改为红色，也没有调用TryParse作为说明命令。
此外，说明指出用户应该能够输入任何正数值。这将包括 8.9 和 216.75 。我想如果你想要最好的成绩，你需要考虑到这一点。看看C# built-in data types。
答案 1 :(得分：0)
你遇到的错误是什么？我认为你必须在行后删除一个：
label3.Text = Convert.ToString(val1 + val2);
答案 2 :(得分：0)
看起来你正在定义一个没有类或类外的方法，请检查所有方法是否在Form1中，请检查是否有更多或缺少括号。
答案 3 :(得分：0)
如果有人遇到这个项目的问题，那么这里是最终产品。一旦它运行，它看起来很不错。
一切都很好，它应该如何！
{ 公共部分类Form1：表格 { 公共Form1（） { 的InitializeComponent（）; }
private void button1_Click(object sender, EventArgs e)
{
int val1;
int val2;
int valid1 = 0;
int valid2 = 0;
if(int.TryParse(textBox1.Text.Trim(), out val1))
{
if(val1>0)
{
valid1 = 1;
caption1.ForeColor = Color.Yellow;
caption1.Visible = true;
caption1.Text = "First value is valid";
}
else
{
caption1.ForeColor = Color.Red;
caption1.Visible = true;
caption1.Text = "Value must be Greater than 0";
}
}
else
{
caption1.ForeColor = Color.Red;
caption1.Visible = true;
caption1.Text = "Value must be Numeric";
}
if(int.TryParse(textBox2.Text.Trim(), out val2))
{
if (val2 > 0)
{
valid2 = 1;
caption2.ForeColor = Color.Yellow;
caption2.Visible = true;
caption2.Text = "First value is valid";
}
else
{
caption2.ForeColor = Color.Red;
caption2.Visible = true;
caption2.Text = "Value must be Greater than 0";
}
}
else
{
caption2.ForeColor = Color.Red;
caption2.Visible = true;
caption2.Text = "Value must be Numeric";
}
if((valid1 > 0)&& (valid2 > 0))
{
label3.Visible = true;
label3.ForeColor = Color.Yellow;
label3.Text = Convert.ToString(val1 + val2);
}
else
{
label3.Visible = false;
}
}
private void button2_Click(object sender, EventArgs e)
{
int val1;
int val2;
int valid1 = 0;
int valid2 = 0;
if(int.TryParse(textBox1.Text.Trim(), out val1))
{
if (val1 > 0)
{
valid1 = 1;
caption1.ForeColor = Color.Yellow;
caption1.Visible = true;
caption1.Text = "First value is valid";
}
else
{
caption1.ForeColor = Color.Red;
caption1.Visible = true;
caption1.Text = "Value must be Greater than 0";
}
}
else
{
caption1.ForeColor = Color.Red;
caption1.Visible = true;
caption1.Text = "Value must be Numeric";
}
if(int.TryParse(textBox2.Text.Trim(), out val2))
{
if (val2 > 0)
{
valid2 = 1;
caption2.ForeColor = Color.Yellow;
caption2.Visible = true;
caption2.Text = "First value is valid";
}
else
{
caption2.ForeColor = Color.Red;
caption2.Visible = true;
caption2.Text = "Value must be Greater than 0";
}
}
else
{
caption2.ForeColor = Color.Red;
caption2.Visible = true;
caption2.Text = "Value must be Numeric";
}
if ((valid1 > 0) && (valid2 > 0))
{
label3.Visible = true;
label3.ForeColor = Color.Yellow;
label3.Text = Convert.ToString(val1 * val2);
}
else
{
label3.Visible = false;
}
}
private void Form1_Load(object sender, EventArgs e)
{
}
private void textBox1_TextChanged(object sender, EventArgs e)
{
}
}
}
答案 4 :(得分：0)
我知道这是两年之后但思想人仍然可能正在寻求帮助。
private void btnAdd_Click(object sender, EventArgs e)
{
int firstNumber, secondNumber;
if (!int.TryParse(txtBxFirstNumber.Text, out firstNumber) || firstNumber < 1)
{
lblResults.Text = "First number needs\n to be numeric and > 0";
lblResults.ForeColor = Color.Red;
lblResults.Visible = true;
txtBxFirstNumber.Clear();
return;
}
if (!int.TryParse(txtBxSecondNumber.Text, out secondNumber) || secondNumber < 1)
{
lblResults.Text = "Second number need\n to be numeric and > 0";
lblResults.ForeColor = Color.Red;
lblResults.Visible = true;
txtBxSecondNumber.Clear();
return;
}
lblResults.ForeColor = Color.Yellow;
lblResults.Visible = true;
lblResults.Text = Convert.ToString(firstNumber + secondNumber);
}
private void btnMultiply_Click(object sender, EventArgs e)
{
int firstNumber, secondNumber;
if (!int.TryParse(txtBxFirstNumber.Text, out firstNumber) || firstNumber < 1)
{
lblResults.Text = "First number needs\n to be numeric";
lblResults.ForeColor = Color.Red;
lblResults.Visible = true;
txtBxFirstNumber.Clear();
return;
}
if (!int.TryParse(txtBxSecondNumber.Text, out secondNumber) && secondNumber < 1)
{
lblResults.Text = "Second number need\n to be numeric";
lblResults.ForeColor = Color.Red;
lblResults.Visible = true;
txtBxSecondNumber.Clear();
return;
}
lblResults.ForeColor = Color.Yellow;
lblResults.Visible = true;
lblResults.Text = Convert.ToString(firstNumber * secondNumber);
}