Graphing in C#

Question

Hello. I got this data in my database

i am using this code to get those data then put them on an array.

 

string item_db= reader.GetString(15);

string amount_db= reader.GetString(17);

string[] str_item= item_db.Split('~');

string[] str_amount = amount_db.Split('~');

 

i will be using them in a graphs. but what i get is this.

 

 

i want to merge those items that are the same as well as merge their value..  so sir how can i do that?.

 

 here's my code for the graph . 

 

 string item_db= reader.GetString(15);

string amount_db= reader.GetString(17);

string[] str_item= item_db.Split('~');

string[] str_amount = amount_db.Split('~');

for (int i = 0; i < str1.Count() - 1; i++)

{

double brand_amount = 0.00;

try

{

if (str1[i] != "")

{

brand_amount = brand_amount + double.Parse(str_amount [i]);

this.chart_p_performance.Series["Series1"].Points.AddXY(str_item[i], brand_amount);

}

}

 

and by the way im using mysql as my database. Thank You..