Calculating column in datagridview - database

Question

I have a form and I'm wondering is it possible to calculate a specific column in a datagridview and output it to a label with the use of a generate button? If yes how do I go about doing it?
Thanks
(this is how the datagridview is set up)
Private Sub refreshdata()
If Not cnn.State = ConnectionState.Open Then
'open connection
cnn.Open()
End If
'create new data and insert the data, Employee, Firstname, lastname, address etc.
Dim da As New OleDb.OleDbDataAdapter("SELECT employeeno as [EmployeeID], " & _
"firstname as [FirstName], lastname as [LastName], address as [Address], department as [Department], workinghours as [WorkingHours], datehired as [DateHired], contactnumber as [ContactNumber] " & _
"FROM employee ORDER BY EmployeeNo", cnn)
Dim dt As New DataTable
'fill data into datatable
da.Fill(dt)
'offer data to be placed in datagridview
Me.DataGridView1.DataSource = dt
'close connection
cnn.Close()
End Sub`enter code here`

Answer 1

I'm not sure what you want to do. If you want just column header in your textBox try this:
C#
private void button1_Click(object sender, EventArgs e)
{
textBox1.Text = dataGridView1.Columns["columnName"].HeaderText;
}
VB
Private Sub button1_Click(sender As Object, e As EventArgs)
textBox1.Text = dataGridView1.Columns("columnName").HeaderText
End Sub
To place your output inside label simply change textBox1.Text to label1.Text. If you want all data written inside your cells of certain column try this:
C#
private void button1_Click(object sender, EventArgs e)
{
StringBuilder sb = new StringBuilder();
foreach (DataGridViewRow row in dataGridView1.Rows)
{
if (row.IsNewRow)
break;
sb.Append(row.Cells["columnName"].Value + " ");
}
textBox1.Text = sb.ToString();
}
VB
Private Sub button1_Click(sender As Object, e As EventArgs)
Dim sb As New StringBuilder()
For Each row As DataGridViewRow In dataGridView1.Rows
If row.IsNewRow Then
Exit For
End If
sb.Append(row.Cells("columnName").Value + " ")
Next
textBox1.Text = sb.ToString()
End Sub
By the way, column name is the column name in design when you right click your DataGridView > Edit columns under design, there should be a "Name" parameter. Hopefully this covers the answer for your question. Cheers!
EDIT:
Added total sum of column output in textBox solution:
C#
private void button1_Click(object sender, EventArgs e)
{
int sum = 0;
foreach (DataGridViewRow row in dataGridView1.Rows)
{
if (row.IsNewRow)
break;
int number;
if (int.TryParse(row.Cells["columnName"].Value.ToString(), out number))
sum += number;
}
textBox1.Text = sum.ToString();
}
VB
Private Sub button1_Click(sender As Object, e As EventArgs)
Dim sum As Integer = 0
For Each row As DataGridViewRow In dataGridView1.Rows
If row.IsNewRow Then
Exit For
End If
Dim number As Integer
If Integer.TryParse(row.Cells("columnName").Value.ToString(), number) Then
sum += number
End If
Next
textBox1.Text = sum.ToString()
End Sub