The dictionary <string, List <string>> has all the values ​​that are the same as for the last entered value

Question

I have a dictionary of string as key and List as value.

And adding an entry as follows: -

allDDLs = new Dictionary<string, List<string>>(); List<string> temp; temp = ddlData.get("INV_DDL_Access_Mechanism", "Type"); allDDLs.Add("Access_Mechanism", temp); temp = ddlData.get("INV_DDL_Application_Operating_System", "OS_Name"); 

So there are 18 entries. But when I debugged the code, I found that all the values ​​are the same as the values ​​of the last entered value. But the keys are fine.

For example, when I get a value for "INV_DDL_Access_Mechanism", I get the same value as for "INV_DDL_Application_Operating_System".

I do not know what is wrong with him. Any help would be greatly appreciated. :-)

Thanks in advance!

EDIT 1: Code for accessing dictionary values:

 List<string> listOfColumns = allDDLs.Keys.ToList<string>(); for(int i = 0; i < listOfColumns.Count(); ++i) { string columnName = listOfColumns[i].ToString(); List<string> tempDDL = new List<string>(); tempDDL = allDDLs[columnName]; List<string> columnValues = DataColumnToList(columnName, excelDataSet.Tables[0]); for (int j = 0; j < columnValues.Count(); ++j ) { if (!tempDDL.Contains(columnValues[j])) { errorReport.Rows[j][columnName.ToString()] = columnValues[j].ToString() + "LOLOLOL"; } } } 

Edit 2: Get method code.

 public List<string> get(string tableName, string parameter) { ds.Clear(); valuesForDDL.Clear(); ds = objDatabase.ByText("Select distinct " + parameter + " from " + tableName + " where Del_Status = 'Available'"); foreach (DataRow row in ds.Tables[0].Rows) { valuesForDDL.Add(row.ItemArray[0].ToString()); } return valuesForDDL; } 

Answer 1

The problem is with your get method.

Each time you call get you return valuesForDDL , and then the next time you clear it and populate it again. Error not found yet?

valuesForDDL should NOT be a field. It is like a global state, and a global state is killing. Make it local and your code will work.

 public List<string> get(string tableName, string parameter) { var valuesForDDL = new List<Whatever>(); var ds = objDatabase.ByText("Select distinct " + parameter + " from " + tableName + " where Del_Status = 'Available'"); foreach (DataRow row in ds.Tables[0].Rows) { valuesForDDL.Add(row.ItemArray[0].ToString()); } return valuesForDDL; } 

EDIT:

Orthogonal note. With LINQ, you can make this code much more enjoyable. I will reorganize your code as follows:

 public IEnumerable<string> Get(string tableName, string parameter) { var ds = objDatabase.ByText("Select distinct " + parameter + " from " + tableName + " where Del_Status = 'Available'"); return ds.Tables[0].Rows.Select(row => row.ItemArray[0].ToString()); } 

Answer 2

You said in your comment:

I clear the list in this code before adding new elements to it. Then return the list.

This may be a problem ... if you return the same List<string> in every ddlData.get() call (using an instance / static field or property), and you just execute List<string>.Clear() , you overwrite the contents of the last returned list.

In ddlData.get() you should make a new List<string>() instead of Clear() existing list.

If this is not your problem, send more code (especially the ddlData.get () method or the whole class).

Answer 3

You are using the same List instance ("temp" in your code).

Create new

 List<string> 

for each dllData.get(".... , and everything will be fine.

 List<string> temp1 = ddlData.get("INV_DDL_Access_Mechanism", "Type"); List<string> temp2 = ddlData.get("INV_DDL_Application_Operating_System", "OS_Name"); .... allDDLs.Add("Access_Mechanism", temp1); allDDLs.Add("Application_Operating_System", temp2); 

EDIT

You would prefer not to use temporary variables, so use:

 allDDLs.Add("Access_Mechanism", ddlData.get("INV_DDL_Access_Mechanism", "Type")); allDDLs.Add("Application_Operating_System", ddlData.get("INV_DDL_Application_Operating_System", "OS_Name")); 

If ddlData.get(...) creates a new List<string> each time, it will work for sure.