Re-adding a List<T>

A Repasky

I am saving a Code and Description in a List.

As I get all the Codes and Description from the database I am storing them in the List. But a few of the Descriptions have a second entry with the same Code to continue the Desciption that does not fit in the first entry field. So I add it to the Description and want to overwrite the List item. Just doing an Add does not do it. So I thought that if I find the index with IndexOf and do a RemoveAt and then do an Add again it would do it and it does not abort, but does not store anything.

Here is the code.

            reasonList.IndexOf(myReason, indx);
            reasonList.RemoveAt(indx);
            reasonList.Add(new ReasonRecord(dataRowItem["Code"].ToString(), myReasonDesc));




 

myReasonDesc is the Description that adds the second Description to the first Description.


 

Say the first Description is "CLAIM WAS PAID UNDER THE NATIONAL PREFERRED" and 
the second is " PROVIDER NETWORK".  I now want to store the 

"CLAIM WAS PAID UNDER THE NATIONAL PREFERRED  PROVIDER NETWORK"



 

How can I do this?
Thanks for any help.


 
arep

9 Replies

Know the answer? Post it — somebody with the same question will find it here.

Suthish Nair15y ago
Lot of ways available which can be easily handled on SQL Server level..

http://stackoverflow.com/questions/194852/concatenate-many-rows-into-a-single-text-string
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A Repasky15y ago

Here is what I did. Since it was concatenating the desc and putting it in the List, but as a 2nd entry, I decided to fix the problem at the other end. When I search for it before I had a foreach, now I am search backword with a for. It works and I am going to go on. If anyone has a better way to get the 2nd entry instead of this, please let me know. Here is the code.

      public static string LookUpReason(string sCode)
      {
         string functionReturnValue = null;
          //foreach (ReasonRecord item in reasonList)
         for (int i = reasonList.Count - 1; i > 0; i--)
         {
            if (sCode.Substring(0, 2) == reasonList[i].Code)
            {
               functionReturnValue = reasonList[i].Description;
               return functionReturnValue;
            }
         }
         functionReturnValue = "";
         return functionReturnValue;

      }


 

Thanks for the help.

arep

Vulpes15y ago
If you need to recover the two parts of the concatenated string, then you'll have to use a different character to a space (Unicode 32) to concatenate them with.

I'd suggest the non-breaking space (Unicode 160) or (HTML) which shouldn't occur in ordinary text but looks like a space when displayed.

So you'd need to replace this line:

myReasonItem.Description += " " + dataRowItem["Description"];

with

myReasonItem.Description += " \xA0" + dataRowItem["Description"];

You can then recover the two parts with:

string[] items = myReasonItem.Description.Split('\xA0');
// items[0] is first part and items[1] is second part
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A Repasky15y ago
It is storing the 2nd desc ok. How do I get at it, if there is the concatenation? There always is not one.
arep
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Vulpes15y ago
The reason why your code is not working is because you're creating a new ReasonRecord object and then trying to remove it from the list. However, there's no way that a new object can be the same as an object already in the list. Consequently, the Remove method can't find it and therefore nothing happens.

However, I don't see why you need to remove the existing item and add a new one to make a simple change like this. I'd have thought that all you'd need to do would be to change the Description property of the existing object like this:

foreach (DataRow dataRowItem in dt.Rows)
{
for(int i = 0; i < reasonList.Count; i++)
{
ReasonRecord myReasonItem = reasonList[i];
if (myReasonItem.Code == (string)dataRowItem["Code"])
{
myReasonItem.Description += " " + dataRowItem["Description"];
}
}
}
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Javeed M Shaikh15y ago
based on your code it looks like:

You have a set of Rows with Duplicate Codes and also another set of record in List with Duplicate code. you want to merge the description from both these and create a new list with unique Codes and merged descriptions, is that correct?
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A Repasky15y ago
I forgot to say that ReasonRecord is a class.
arep
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A Repasky15y ago

I changed the code slightly.  I found out the Add is working, but the Remove is not.  So when I am searching later 
on for the Code, it find the first one and not the second.  I only want to save one occurence.  So here is the code.
Thanks, arep



 
         DetailRecord detailRec = new DetailRecord();
         string sCode = "";
         ReasonRecord myReason = new ReasonRecord();


          foreach (DataRow dataRowItem in dt.Rows)
         {
            //Add Description and save, if code is the same
            foreach (ReasonRecord myReasonItem in reasonList)
            {
               if (myReasonItem.Code == (string)dataRowItem["Code"])
               {
                  myReason.Code = myReasonItem.Code;
                  myReason.Description = myReasonItem.Description + " " + dataRowItem["Description"];
               }
            }
          //Save reason code
         if (sCode == dataRowItem["Code"].ToString())
         {
            reasonList.Remove(myReason);
            reasonList.Add(new ReasonRecord(dataRowItem["Code"].ToString(), myReason.Description));
         }
         else

         { 
           reasonList.Add(new ReasonRecord(dataRowItem["Code"].ToString(), dataRowItem["Description"].ToString()));
          }
          sCode = dataRowItem["Code"].ToString();
         }

Javeed M Shaikh15y ago
so what you are trying to do here is add the concatenanted description in the reasonlist. Following is my understanding:

            reasonList.IndexOf(myReason, indx); --> Search for code from the index and below.
            reasonList.RemoveAt(indx); --> Assuming the code is found and you remove that entry.
            reasonList.Add(new ReasonRecord(dataRowItem["Code"].ToString(), myReasonDesc)); --> You add to the end of the list the code and the concatenated desc.

so is the last line not adding anything, please provide more code snippet to understand better.

Please do not forget to mark "Accepted Answer".
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