how to edit data table column header names using c#?

Sujeet Raman

I have some logical block in my c# program,as i am new to c# programming.

i have a data-table with duplicate header column names .I have to change my duplicate header like concatenate the name of the prior column to make these headers unique.Table names are coming dynamically.

Current datatable

Expecting

what i have tried and blocked here below

public DataTable RemoveDuplicateRows(DataTable dTable)

{

string[] columnNames = dTable.Columns.Cast().Select(x => x.ColumnName).ToArray();

for (int i = 0; i < columnNames.Length; i++)

{

columnNames[i] = columnNames[i].Split('.')[0].Trim();

}

for (int i = 0; i < columnNames.Length; i++)

{

//create nested loop for compare current values with actual value of arr

for (int j = i + 1; j < columnNames.Length; j++)

{

if (columnNames[i] == columnNames[j])

{

var previous = columnNames[i - 1];

var current = columnNames[i];

columnNames[i] = current + previous;

//blocked here

//only one header is concatenating

//how can i add this newly edited columns to my datatable

}

return dTable; //cant get updated coloumn headers

}

7 Replies

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Nisha Regil6y ago
In your code dont use the below lines

for (int i = 0; i < distinctArray.Length; i++)
{
dTable= headers from distinctArray
}

The distinctArray itself returns all the values in your required format.
Sujeet Raman6y ago
Hi nisha I have doubt here in your code:i need to replace the old headers with this new concatinated headers in the same datatable "dTable".I have values but just table headers has to change

In my code i am taking the table headers like,
string[] columnNames = dTable.Columns.Cast().Select(x => x.ColumnName).ToArray();
so how i can add
for (int i = 0; i < distinctArray.Length; i++)
{
dTable= headers from distinctArray
}
i failed to add when i am doing like
foreach (string item in distinctArray)
{
dTable.Rows.Add(item);
}
return dTable;
}
Nisha Regil6y ago
I have tried to replicate your requirement. I have taken a string array instead of DataTable
string[] columns = { "Volvo", "BMW", "Ford", "Mazda", "Ford", "Volvo" ,"one"}; // All columns
List<string> newcolumnsList = new List<string>(); // list for new array of columns
String psearchString = "";
for (int i = 0; i < columns.Length; i++)
{
String searchString = columns[i];
int index = newcolumnsList.IndexOf(searchString); // check if column name already exists
if (index == -1)
{
newcolumnsList.Add(searchString);
}
else
{
psearchString = columns[i - 1]; // get previous name.
newcolumnsList.Add(searchString +"+"+ psearchString);
}
}
var distinctArray = newcolumnsList.ToArray(); // array as per expectation.
// Create a new table with Dynamically adding the colums int table in loop below
for (int i=0;i< distinctArray.Length; i++)
{
//
}
Please see it this is useful.
Sujeet Raman6y ago
the coloumn name is coming like name,name.1,name.2 i need to convert to like name.1 to name+previous
Nisha Regil6y ago
In DataTable if you have 2 columns with the same name it will throw error A column named 'Columnname' already belongs to this DataTable.

Is there no error from Current Datatable with same columnnames?
Sujeet Raman6y ago
yes i am sure.All i need to make my coloumns unique using this methode.Adding prior column to the duplicate coloumn
Nisha Regil6y ago
Are you sure, you want to concat only the ColumnName and not the rowdata for the datatable?