read and modify/update cell in datatable - asp.net

Question

Scenario
I want to calculate and rank the suitability of healthcare workers for a particular patients, by comparing parameters such as race, religion, gender, spoken language, etc.
HealthcareWorker table
----------------------
ID (int)
name (varchar)
race (varchar)
religion (varchar)
gender (varchar)
german (bit)
french (bit)
english (bit)
Patient table
-------------
ID (int)
name (varchar)
race (varchar)
religion (varchar)
gender (varchar)
german (bit)
french (bit)
english (bit)
Webpage Layout
On page1.aspx there will be a gridview table showing the details of all Patients.
User will then select a Patient and be directed to page2.aspx
On page2.aspx there will a table showing the details of each Healthcare Worker and his suitability with the selected patient in the form of a score. there will also be checkboxes inside the table in order to assign more than one Healthcare Worker to the selected Patient.
page2.aspx
| ID | name | religion | gender | german | french | english | score | |
|----+-------+----------+---------+----------+---------+----------+--------+----------|
| 4 | mary | | f | 1 | 0 | 1 | 132 | checkbox |
| 2 | john | | m | 0 | 1 | 1 | 125 | checkbox |
| 3 | tim | | m | 1 | 0 | 1 | 98 | checkbox |
| 1 | jane | | f | 1 | 1 | 0 | 55 | checkbox |
the computation of the score will be something like this:
if patient.race = healthcareworker.race then healthcarework.score +10
if patient.religion = healthcareworker.religion then healthcarework.score +10
if at least one of patient's language match with healthcareworker's language then healthcarework.score +10
code:
Dim strCon As String = ConfigurationManager.ConnectionStrings("ConnectionString1").ConnectionString
Dim con As New SqlConnection(strCon)
Dim query As String = "select *, CAST ( 0 as int ) score from HealthcareWorker;"
Dim cmd As SqlCommand = New SqlCommand(query, con)
con.Open()
Dim dr As SqlDataReader = cmd.ExecuteReader(CommandBehavior.CloseConnection)
Dim dt As DataTable = New DataTable()
dt.Load(dr)
'code to read cell
'code to compare and compute
'code to update the score in each row
GridView1.DataSource = dt
GridView1.DataBind()
con.Close()
How do I read and modify the cells in the datatable?
I want read and compare the data from some cells in each row and then update the score value.
I need to update the score for each row so I am going to need a loop but I do not know the number of rows that will be loaded into the datatable before hand.
How do I get the number of rows in the datatable?
edit/update: reworked the entire question to provide (a lot) more background information

Answer 1

The last question is answered easily:
I need to update the score for each row so I am going to need a loop
but I do not know the number of rows that will be loaded into the
datatable before hand. How do I get the number of rows in the
datatable?
You just have to use the Rows.Count property:
Dim rowCount As Int32 = tblPatient.Rows.Count ' tblPatient => DataTable '
If you want to loop all rows you can use a foreach:
For Each row As DataRow In tblPatient.Rows
' ... '
Next
or a for-loop:
For i As Int32 = 0 To tblPatient.Rows.Count - 1
Dim row As DataRow = tblPatient.Rows(i)
' ... '
Next
To update the rows you can use the SetField extension method which also support nullable-types:
For Each row As DataRow In tblPatient.Rows
Dim id As Int32 = row.Field(Of Int32)("ID")
Dim race As String = row.Field(Of String)("Race")
row.SetField("Score", CalculateScore(row))
Next
Sorry that i cannot provide you the correct calculation but it's still not clear how you want to calculate it since you haven't provided the source of the Score(theres no column). But it might give you an idea anyway.