Display DataGridView values in text boxes based on matching values - vb.net - vb.net

Question

I have an SQL query that returns 2 columns of values:
country | number
NA | 1
IN | 2
CN | 3
DE | 4
And so on.
I am trying to do one of the following:
Assign these values to variables I can copy to an excel workbook
Or just use the DGV as a medium to copy values to text boxes.
For example, I have a form with country labels and textboxes next to them. I would want to click a button and have the data copied to the matching text box.
DGV number value where DGV row value = CN would be 3 and that value would be copied to the CN value text box.

Answer 1

If you are only using the DGV as a medium, but not actually displaying it, use a dictionary instead. Output the SQLDataReader using the SQLcommand(cmd) with the country code being the key and the number being the value. Then its as simple as:
Dim dc As Dictionary(Of String, String) = New Dictionary(Of String, String)
Dim cmd As SqlCommand = "your query string"
cmd.Connection.ConnectionString = "your con string"
Using sqlrdr As SqlDataReader = cmd.ExecuteReader()
While (sqlrdr.Read())
dc.Add(sqlrdr(0), sqlrdr(1))
End While
End Using
Then just output to the textbox:
txtNA.Text = dc.Item("NA")

Answer 2

If the countries are fixed as your question refers, then you could use something like this:
First, use the names of the countries to name the TextBoxes (txtNA, txtIN, txtCN,...)
Then you can put this code:
Try
For i = 0 To DataGridView1.RowCount - 1
Me.Controls("txt" & DataGridView1.Rows(i).Cells(0).Value.ToString).Text = _
DataGridView1.Rows(i).Cells(1).Value.ToString()
Next
Catch
End Try

Answer 3

The following will not work 'as is' if using classes via dragging tables from the data source window in the ide. We would need to cast objects not to a DataTable but to the class definition in a TableAdapter, DataSet and BindingSource.
Here is a method which reads from SQL-Server database table, places data into a DataTable, data table become the data source for a BindingSource which becomes the data source for the DataGridView. Using a BindingSource we now use the BindingSource to access row data rather than the DataGridView and it's always best to go to the data source rather than the user interface.
BindingSource.Current is a DataRowView, drill down to Row property then field language extension method to get strongly typed data for the current row if there is a current row as you will note I am using two forms of assertions, first, do we have a data source and is the data source populated then we see if there is indeed a current row.
From here we can set variable, properties or control text to the field values of the current row.
Note in form load I seek a specific country (totally optional) and then if found go to that row.
Least but not last, I like using xml literals when doing SQL in code so there is no string concatenation and we can format the statement nicely.
Public Class Form1
''' <summary>
''' Permits obtaining row data in DataGridView
''' </summary>
''' <remarks></remarks>
Dim bsCountries As New BindingSource
Public Property Country As String
Public Property CountryNumber As Integer
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim dt As New DataTable
Using cn As New SqlClient.SqlConnection With
{
.ConnectionString = My.Settings.KarenDevConnectionString
}
Using cmd As New SqlClient.SqlCommand With {.Connection = cn}
' xml literal to make command text
cmd.CommandText =
<SQL>
SELECT [ID],[Country],[Number]
FROM [Countries]
</SQL>.Value
cn.Open()
dt.Load(cmd.ExecuteReader)
dt.Columns("ID").ColumnMapping = MappingType.Hidden
bsCountries.DataSource = dt
DataGridView1.DataSource = bsCountries
' let's try and move to a country
Dim index As Integer = bsCountries.Find("Country", "CN")
If index > -1 Then
bsCountries.Position = index
End If
End Using
End Using
End Sub
''' <summary>
''' Put field values into TextBoxes
''' </summary>
''' <remarks></remarks>
Private Sub DoWork()
If bsCountries.DataSource IsNot Nothing Then
If bsCountries.Current IsNot Nothing Then
Dim row As DataRow = CType(bsCountries.Current, DataRowView).Row
TextBox1.Text = row.Field(Of String)("Country")
TextBox2.Text = row.Field(Of Integer)("Number").ToString
' we can also do this
Me.Country = row.Field(Of String)("Country")
Me.CountryNumber = row.Field(Of Integer)("Number")
End If
End If
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
DoWork()
End Sub
End Class