英文:
A "dry" principle case
问题
需要检查用户输入的数据，并在输入不正确时在屏幕上显示通知。我使用了以下方法，但我觉得它不太符合"不要重复自己"的原则。有没有人有简化的想法？
int productid = 0;
string errorMessage = "数据格式不正确：\n",
productName = "", productGroup = "", productType = "";
if (!int.TryParse(ProductIdTB.Text, out productId))
{
errorMessage += "+ 产品编号\n";
}
if (string.IsNullOrEmpty(ProductNameTB.Text))
{
errorMessage += "+ 产品名称\n";
}
else
{
productName = ProductNameTB.Text;
}
if (string.IsNullOrEmpty(ProductGroupTB.Text))
{
errorMessage += "+ 产品组\n";
}
else
{
productGroup = ProductGroupTB.Text;
}
if (string.IsNullOrEmpty(ProductType.Text))
{
errorMessage += "+ 产品类型";
}
else
{
productType = ProductType.Text;
}
if (errorMessage.Split(' ').Length > 1)
{
MessageBox.Show(errorMessage);
return;
}
希望这对你有帮助。
英文:
there is a need to check the data entered by the user and display a notification on the screen in case of incorrect input. I used the following method, but it seems to me that it don't quite fit into the principle of "don't repeat yourself". Does anyone have any ideas for simplification?
int productid = 0;
string errorMessage = "Неправильный формат данных:\n",
productName = "", productGroup = "", productType = "";
if (!int.TryParse(ProductIdTB.Text, out productId))
{
errorMessage += "+ Номер продукта\n";
}
if (string.IsNullOrEmpty(ProductNameTB.Text))
{
errorMessage += "+ Название продукта\n";
}
else
{
productName = ProductNameTB.Text;
}
if (string.IsNullOrEmpty(ProductGroupTB.Text))
{
errorMessage += "+ Группа продукта\n";
}
else
{
productGroup = ProductGroupTB.Text;
}
if (string.IsNullOrEmpty(ProductType.Text))
{
errorMessage += "+ Вид продукта";
}
else
{
productType = ProductType.Text;
}
if (errorMessage.Split(' ').Length > 1)
{
MessageBox.Show(errorMessage);
return;
}
答案1
得分: 1
我可以想象构建一个执行这些检查并收集所有错误的类，无论是以字符串或字符串列表的形式。
class ErrorMessageBuilder
{
string totalmessage = "";
void AppendErrorIfEmpty(TextBox t, string textboxname)
{
if (t.Text.IsNullOrEmpty())
{
totalmessage += textboxname + " 不能为空" + Environment.NewLine;
}
}
void AppendErrorIfNotInt(TextBox t, string textboxname)
{
int value;
if (!int.TryParse(t.Text, out value))
{
totalmessage += textboxname + " 必须是整数" + Environment.NewLine;
}
}
}
这将减少代码量到
var emb = ErrorMessageBuilder();
emb.AppendErrorIfNotInt(ProductIdTB, "产品 ID");
emb.AppendErrorIfEmpty(ProductNameTB, "产品名称");
...
由于这看起来像是 WinForms 开发，您还可以查看 ErrorProvider 类。与工具提示一样，它允许每个控件有一个错误消息。也许这会更加用户友好。
英文:
I can imagine building a class that does the checks for you and collects all errors, either in a string or a list of strings.
class ErrorMessageBuilder
{
string totalmessage = "";
void AppendErrorIfEmpty(TextBox t, string textboxname)
{
if (t.Text.IsNullOrEmpty())
{
totalmessage += textboxname + " can't be empty" + Environment.NewLine;
}
}
void AppendErrorIfNotInt(TextBox t, string textboxname)
{
int value;
if (!int.TryParse(t.Text, out value))
{
totalmessage += textboxname + " must be an integer number" + Environment.NewLine;
}
}
}
This would reduce the code to
var emb = ErrorMessageBuilder();
emb.AppendErrorIfNotInt(ProductIdTB, "Product ID");
emb.AppendErrorIfEmpty(ProductNameTB, "Product Name");
...
Since this looks like WinForms development to me, you can also have a look at the ErrorProvider class. Like with tooltips, it allows one error message per control. Perhaps that would be even more user-friendly.
答案2
得分: 0
根据使用情况，考虑到字符串的不可变性，它可能不会很好地扩展。对于每个 += 操作，您都会创建一个新的字符串实例，字符串越大，占用的内存和垃圾越多...
考虑使用 StringBuilder 以及它的 Append/AppendFormat 方法。
英文:
Depending on how much this is used, it might not scale out very well considering the immutability of strings. For every += you are creating a new string instance, the bigger the string the more memory and garbage...
Consider StringBuilder and it's Append/AppendFormat methods.
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