Hi amiteshverma,

According to your description, my understanding is that you would like to fetch datatable columns value into string array.

If so, please try to refer to the following code:

string[] strArr = new string[dt.Rows.Count];
			int i=0;
			foreach (DataRow r in dt.Rows)
			{
				strArr[i] = r["ColumnName"].ToString();
				i++;
			}

Hope it helps.

Best Regards,
Terry Guo