How to reduce a if statements?-CodePudding

I have a object that has the result of a query, this object has date´s fields and i need to deal where the field has the date '01-01-1991'change to null. How can i simplify this if statement?

if(item.date01 == '01-01-1991')
   item.date01 = null;

if(item.date02 == '01-01-1991')
   item.date02 = null;

if(item.date03 == '01-01-1991')
   item.date03 = null;

if(item.date04 == '01-01-1991')
   item.date04 = null;

i tried to use foreach, but i didnt know how...

foreach(var item in itens)
{
    if(item.obj == '01-01-1991')
      item.obj = null;
}

CodePudding user response：

I'm not sure if you have a working example, since the single quotes in `'01-01-1991' are not valid to use in a string or datetime.

Also, you mention that the date01, date02, ... are fields. In that case, you can do the following:

var item = new DataItem();

void CheckAndSet(ref string? date)
{
    if (date == "01-01-1900")
    {
        date = null;
    }
}

CheckAndSet(ref item.date01);
CheckAndSet(ref item.date02);
CheckAndSet(ref item.date03);
CheckAndSet(ref item.date04);

public class DataItem
{
    public string? date01;
    public string? date02;
    public string? date03;
    public string? date04;
}

To elaborate, you can use the ref keyword to keep the reference to the original variable, which in this case is the date0x field in the DataItem class.

CodePudding user response：

iterate each item of items

foreach(var item in items)
{
    this.CheckAndSetDate(ref item.date01,"01-01-1991");
    this.CheckAndSetDate(ref item.date02,"01-01-1991");
    this.CheckAndSetDate(ref item.date03,"01-01-1991");
    this.CheckAndSetDate(ref item.date04,"01-01-1991");
}

then create validate function

public void CheckAndSetDate(ref string date, string value)
{
   date = date == value ? null : date;
}

foreach(var item in items)
{
    item.date01 = this.CheckAndSetDate(item.date01,"01-01-1991");
    item.date02 = this.CheckAndSetDate(item.date02,"01-01-1991");
    item.date03 = this.CheckAndSetDate(item.date03,"01-01-1991");
    item.date04 = this.CheckAndSetDate(item.date04,"01-01-1991");
}

public stringCheckAndSetDate(ref string date, string value)
{
   return date == value ? null : date;
}

CodePudding user response：

You can use Reflection.

foreach(var element in (IEnumerable)item)
     {
          Type type = element.GetType();
          PropertyInfo[] properties = type.GetProperties();
          foreach(PropertyInfo p in properties)
          {
              if(p.GetValue(element,null) == "01-01-1991")
              {
                  p.SetValue(item, null, null)
              }

           } 
      }