返回false，如果类型属性等于null或0。

huangapple
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英文:

Return false if type properties equals null or 0

问题

I tried following the method as follows here: link. However, when instantiating Order newOrder = new Order();. I cannot simply just implement bool props = newOrder.ArePropertiesNotNull(). What am I supposed to add to my Order class? And where do I implement the function for ArePropertiesNotNull<T>(this T obj)? I would like to know if there is a way to return false if the value returned equals 0 or null?

Here is my code:

OrderProdRepository.cs

  1. ...
  2. public bool ReadFromFile(string _date)
  3. {
  4.     taxesFile.ReadFile();
  5.     productsFile.ReadFile();
  7.     string orderFileName = "C:\\tempfolder\\Orders_" + _date + ".txt";
  9.     List<string> lines = File.ReadAllLines(orderFileName).ToList();
  11.     foreach (var line in lines.Skip(1))
  12.     {
  13.         List<string> entry = line.Split(',').ToList();
  15.         Order newOrder = new Order();
  16.         int.TryParse(entry[0], out int orderNumber);
  17.         newOrder.OrderNumber = orderNumber;
  18.         newOrder.Date = _date;
  19.         newOrder.CustomerName = entry[1];
  20.         newOrder.State = taxesFile.StateAbbreviation(entry[2]);
  21.         newOrder.StateName = taxesFile.StateName(newOrder.State);
  22.         decimal.TryParse(entry[3], out decimal taxRate);
  23.         newOrder.TaxRate = taxesFile.TaxRate(taxRate);
  24.         newOrder.ProductType = productsFile.ProductType(entry[4]);
  25.         decimal.TryParse(entry[5], out decimal area);
  26.         newOrder.Area = area;
  27.         decimal.TryParse(entry[6], out decimal costPerSquareFoot);
  28.         newOrder.CostPerSquareFoot = productsFile.CostPerSquareFoot(costPerSquareFoot);
  29.         decimal.TryParse(entry[7], out decimal laborCostPerSquareFoot);
  30.         newOrder.LaborCostPerSquareFoot = productsFile.LaborCostPerSquareFoot(laborCostPerSquareFoot);
  31.         decimal.TryParse(entry[8], out decimal materialCost);
  32.         newOrder.MaterialCost = materialCost;
  33.         decimal.TryParse(entry[9], out decimal laborCost);
  34.         newOrder.LaborCost = laborCost;
  35.         decimal.TryParse(entry[10], out decimal tax);
  36.         newOrder.Tax = tax;
  37.         decimal.TryParse(entry[11], out decimal total);
  38.         newOrder.Total = total;
  40.         orderList.Add(newOrder);
  41.     }
  42.     return true;
  43. }
  44. ...
英文:

I tried following the method as follows here: https://stackoverflow.com/questions/50128815/checking-if-object-has-null-in-every-property . However, when instantiating Order newOrder = new Order();. I cannot simple just implement bool props = newOrder.ArePropertiesNotNull(). What am I supposed to add to my Order class? And where do I implement the function for ArePropertiesNotNull&lt;T&gt;(this T obj)? I would like to know if there is a way to return false if value returned equals 0 or null?

Here is my code:

OrderProdRepository.cs

  1. ...
  2. public bool ReadFromFile(string _date)
  3.         {
  4.             taxesFile.ReadFile();
  5.             productsFile.ReadFile();
  7.             string orderFileName = $&quot;C:\\tempfolder\\Orders_{_date}.txt&quot;;
  9.             List&lt;string&gt; lines = File.ReadAllLines(orderFileName).ToList();
  11.             foreach (var line in lines.Skip(1)) //?? new List&lt;string&gt;(0)
  12.             {
  13.                 List&lt;string&gt; entry = line.Split(&#39;,&#39;).ToList();
  15.                 Order newOrder = new Order();               
  16.                 int.TryParse(entry[0], out int orderNumber);
  17.                 newOrder.OrderNumber = orderNumber;
  18.                 newOrder.Date = _date;
  19.                 newOrder.CustomerName = entry[1];
  20.                 newOrder.State = taxesFile.StateAbbreviation(entry[2]);
  21.                 newOrder.StateName = taxesFile.StateName(newOrder.State);
  22.                 decimal.TryParse(entry[3], out decimal taxRate);
  23.                 newOrder.TaxRate = taxesFile.TaxRate(taxRate);
  24.                 newOrder.ProductType = productsFile.ProductType(entry[4]);
  25.                 decimal.TryParse(entry[5], out decimal area);
  26.                 newOrder.Area = area;
  27.                 decimal.TryParse(entry[6], out decimal costPerSquareFoot);
  28.                 newOrder.CostPerSquareFoot = productsFile.CostPerSquareFoot(costPerSquareFoot);
  29.                 decimal.TryParse(entry[7], out decimal laborCostPerSquareFoot);
  30.                 newOrder.LaborCostPerSquareFoot = productsFile.LaborCostPerSquareFoot(laborCostPerSquareFoot);
  31.                 decimal.TryParse(entry[8], out decimal materialCost);
  32.                 newOrder.MaterialCost = materialCost;
  33.                 decimal.TryParse(entry[9], out decimal laborCost);
  34.                 newOrder.LaborCost = laborCost;
  35.                 decimal.TryParse(entry[10], out decimal tax);
  36.                 newOrder.Tax = tax;
  37.                 decimal.TryParse(entry[11], out decimal total);
  38.                 newOrder.Total = total;
  41.                 orderList.Add(newOrder);
  42.             }
  43.             return true;
  44.         }
  45. ...

答案1

得分: 0

你需要将这个方法创建为扩展方法。它应该被定义在静态类中：

  1. public static class ObjectExtensions
  2. {
  3.     public static bool ArePropertiesNotNull<T>(this T obj)
  4.     {
  5.         return typeof(T).GetProperties().All(propertyInfo => propertyInfo.GetValue(obj) != null);
  6.     }
  7. }
英文:

You need to create this method an extension method. It should be defined in static class:

  1. public static class ObjectExtensions
  2. {        
  3.     public static bool ArePropertiesNotNull&lt;T&gt;(this T obj)
  4.     {
  5.         return typeof(T).GetProperties().All(propertyInfo =&gt; propertyInfo.GetValue(obj) != null);
  6.     }
  7. }

答案2

得分: 0

以下是已翻译的代码部分：

  1. 我认为你需要一个函数来检查每一行是否包含`null`和/或`0`值：
  3. private bool IsValidLine(string line)
  4. {
  5.     if (line == null)
  6.         return false;
  8.     var arr = line.Split(',');
  10.     //Uncomment this if splitting the line will always return 11 items array.
  11.     //if (arr.Length < 11)
  12.     //    return false;
  14.     return arr.Aggregate(0, (n, s) =>
  15.     (decimal.TryParse(s, out decimal d) && d == 0) ||
  16.     string.IsNullOrWhiteSpace(s) ? n + 1 : n) == 0;
  17. }
  19. 你可以在你的代码中如下使用它：
  21. public bool ReadFromFile(string _date)
  22. {
  23.     var orderFileName = $"C:\\tempfolder\\Orders_{_date}.txt";
  24.     var lines = File.ReadAllLines(orderFileName);
  26.     foreach (var line in lines.Skip(1))
  27.     {
  28.         //If parsing any line returns false.
  29.         if (!IsValidLine(line))
  30.             return false;
  32.         //Or if you need to create a list of the valid Order entries.
  33.         if (IsValidLine(line))
  34.         {
  35.             var order = new Order();
  37.             //...
  39.             orderList.Add(newOrder);
  40.         }
  41.     }
  42.     return true;
  43. }

希望这对你有帮助。如果你需要更多帮助，请随时提问。

英文:

I think you need a function to check each line for null and/or 0 values:

  1. private bool IsValidLine(string line)
  2. {
  3.     if (line == null)
  4.         return false;
  6.     var arr = line.Split(&#39;,&#39;);   
  8.     //Uncomment this if splitting the line will always return 11 items array.
  9.     //if (arr.Length &lt; 11)
  10.     //    return false;      
  12.     return arr.Aggregate(0, (n, s) =&gt; 
  13.     (decimal.TryParse(s, out decimal d) &amp;&amp; d == 0) || 
  14.     string.IsNullOrWhiteSpace(s) ? n + 1 : n) == 0;
  15. }

You can use it in your code as follows:

  1. public bool ReadFromFile(string _date)
  2. {
  3.     var orderFileName = $&quot;C:\\tempfolder\\Orders_{_date}.txt&quot;;
  4.     var lines = File.ReadAllLines(orderFileName);
  6.     foreach (var line in lines.Skip(1))
  7.     {
  8.         //If parsing any line returns false.
  9.         if (!IsValidLine(line))
  10.             return false;
  12.         //Or if you need to create a list of the valid Order entries.
  13.         if (IsValidLine(line))
  14.         {
  15.             var order = new Order();
  17.             //...
  19.             orderList.Add(newOrder);
  20.         }
  21.     }
  22.     return true;
  23. }

Alternatives:

  • Add a static function in the Order class to parse a given line and return a new object of Order type if the line is valid. Something like this.
  • If its not too late, then consider using a local database or serialization. Something like this and maybe this if you don't mind a vb.net example.

huangapple
  • 本文由 发表于 2020年1月4日 12:58:39
  • 转载请务必保留本文链接：https://go.coder-hub.com/59588026.html
  • c#
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