CODEWITHSUNDEEP
c#datatable
SamFisher83
SamFisher83

Reputation: 3995

duplicate datatable column names

I have a datable with column names I0,I1,I2 etc. However these aren't actual column names. I store the column names in another table.

I then have a loop to map the actual column names as follows:

for (int i = 0; i < dt_key.Rows.Count; i++)
{
    dt_data.Columns[i].ColumnName = dt_key.Rows[i][0].ToString();
}

I get the following errors:

A column named 'Pressure' already belongs to this DataTable.

and

A column named 'Size' already belongs to this DataTable.

Ultimately I am trying to write this to a xml file:

dt_data.WriteXml(filename);

This works but I end up the column names I0..I22

There are similar questions to this, but they are trying to make datatables with duplicate columns names. I am just trying to print out a table with duplicate column names. What is a good method to do this?

Edit:

I can do the following:

for (int i = 0; i < dt_key.Rows.Count; i++)
{
    dt_data.Columns[i].ColumnName = dt_key.Rows[i][0].ToString() + " " + dt_data.Columns[i].ColumnName;
}

Upvotes: 1

Views: 27047

Answers (4)

AHAMED AAQIB
AHAMED AAQIB

Reputation: 473

You can not duplicate Column names by using Data Table.Consider this and find another solution .

If you try to duplicate Column name then it will show an error like that you mentioned.

A column named 'Pressure' already belongs to this Data Table .

In here you try to duplicate Column name 'Pressure' that's why that error comes.

Upvotes: 0

SiuFay
SiuFay

Reputation: 343

Maybe you can make use of the DataColumn.Caption property to store the column display name:

https://msdn.microsoft.com/en-us/library/system.data.datacolumn.caption(v=vs.110).aspx

Upvotes: 2

Amol Kadam
Amol Kadam

Reputation: 85

for (int i = 0; i < dt_key.Rows.Count; i++)
    {
       if(dt_data.Columns.Contains(dt_key.Rows[i][0].ToString()))             
         dt_data.Columns[i].ColumnName = dt_key.Rows[i][0].ToString() + "  " ;
      else
         dt_data.Columns[i].ColumnName = dt_key.Rows[i][0].ToString();
    }

However adding a same column name is a bad practise,still you could achieve that by adding a space at the end of column name to make it unique.

Upvotes: 5

dana
dana

Reputation: 18105

I think the short answer to your question is that there is no way to have duplicate column names using a DataTable. What exactly are you using this XML for? There are lots of alternate ways to generate XML that give you a lot more fine grained control.

You could manually create your file using an XmlWriter object. This method creates an XmlWriter that writes to a file.

Upvotes: 6

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