How to convert total time to minutes - vb.net

Question

This was the error msg im gettingenter image description hereI have a database that has a row "Total_Time" (time).
It is in the format HH:MM:SS. I need the code to convert the "Total_time" to minutes.
For example, if Total_time = 01:30:00, the answer should be Total_minutes = 90,
and I want to multiply the total_minutes with "Other" (int variable).
Below is what I have tried:
Private Sub Button5_Click(sender As Object, e As EventArgs) Handles Button5.Click
con = New System.Data.SqlClient.SqlConnection
Try
con.ConnectionString = "Data Source=Vicky-pc\sqlexpress;Initial Catalog=customer_details;Integrated Security=True;Pooling=False"
con.Open()
Dim cm As SqlClient.SqlCommand
cm = New SqlClient.SqlCommand("SELECT * FROM customer_details WHERE Id=#id", con)
cm.Parameters.AddWithValue("#id", TextBox5.Text)
dr = cm.ExecuteReader()
While dr.Read()
Dim tt As Double
tt = dr("Total_Time").ToString
Dim other As Double
other = dr("Other").ToString
Dim str() As String
Dim strmin As Double
str = Split(tt.ToString, ":")
strmin = (CDbl(str(1)) * 60 + CDbl(str(2)) + CDbl(str(3)) / 60).ToString
Dim total As Decimal
total = strmin + other
Label7.Text = total.ToString
End While
Catch ex As Exception
End Try
End Sub
but when i click nothing is happening label7 is not displaying any values
Thanks in advance.

Answer 1

Dim Total_minutes As Double = CDate("1:23:45").TimeOfDay.TotalMinutes ' 83.75
To avoid similar errors, I would highly recommend using Option Strict
Dim Total_Time As DateTime = Convert.ToDateTime(dr!Total_Time)
Dim Total_minutes# = Total_Time.TimeOfDay.TotalMinutes
Dim Other# = Val(dr!Other)
Dim total# = Total_minutes * Other
Label7.Text = total.ToString

Answer 2

Try below
Private Sub Button5_Click(sender As Object, e As EventArgs) Handles Button5.Click
con = New System.Data.SqlClient.SqlConnection
Try
con.ConnectionString = "Data Source=Vicky-pc\sqlexpress;Initial Catalog=customer_details;Integrated Security=True;Pooling=False"
con.Open()
Dim cm As SqlClient.SqlCommand
cm = New SqlClient.SqlCommand("SELECT * FROM customer_details WHERE Id=#id", con)
cm.Parameters.AddWithValue("#id", TextBox5.Text)
dr = cm.ExecuteReader()
While dr.Read()
Dim other As TimeSpan
Dim tt As TimeSpan
If TimeSpan.TryParse(dr("Total_Time"), tt) Then
If TimeSpan.TryParse(dr("Other"), other) Then
tt = tt.Add(other)
Else
'Do something like show error message for incorrect data for dr("Other")
End If
Label7.Text = tt.TotalMinutes.ToString
Else
'Do something like show error message for incorrect data for dr("Total_Time")
End If
End While
Catch ex As Exception
End Try
End Sub
If time is more than 24:00:00, use below code
Private Sub Button5_Click(sender As Object, e As EventArgs) Handles Button5.Click
con = New System.Data.SqlClient.SqlConnection
Try
con.ConnectionString = "Data Source=Vicky-pc\sqlexpress;Initial Catalog=customer_details;Integrated Security=True;Pooling=False"
con.Open()
Dim cm As SqlClient.SqlCommand
cm = New SqlClient.SqlCommand("SELECT * FROM customer_details WHERE Id=#id", con)
cm.Parameters.AddWithValue("#id", TextBox5.Text)
dr = cm.ExecuteReader()
While dr.Read()
Try
Dim dataTime As String = dr("Total_Time").ToString
dataTime = dataTime.Split("."c)(0).ToString
Dim tt As New TimeSpan(Integer.Parse(dataTime.Split(":"c)(0)), Integer.Parse(dataTime.Split(":"c)(1)), Integer.Parse(dataTime.Split(":"c)(2)))
dataTime = dr("Other").ToString
dataTime = dataTime.Split("."c)(0).ToString
Dim other As New TimeSpan(Integer.Parse(dataTime.Split(":"c)(0)), Integer.Parse(dataTime.Split(":"c)(1)), Integer.Parse(dataTime.Split(":"c)(2)))
tt = tt.Add(other)
dataTime = tt.TotalMinutes.ToString
Catch ex As Exception
'do something here as string is not a time
End Try
End While
Catch ex As Exception
End Try
End Sub

Answer 3

Don't keep switching to strings... and use a Timespan
If your label never changes then the routine must be erroring out, examine the error from the catch statement. However from your image it looks like Other has no value.
And you should ALWAYS test for dbnull when using databases. DBNull has some weird behaviours in Math and Boolean comparisons.
Replace your while loop with this
If Not Dr.read OrElse IsDBNull(Dr("Total_time")) OrElse IsDBNull(Dr("Other")) Then
Label7.text = "ERR"
Else
Dim ts As TimeSpan = TimeSpan.Parse(dr("Total_time").ToString)
Label7.text = (ts.TotalMinutes * Dr("Other")).ToString
End If
PS: Your question says multiply by Other but your form/code says Add... I went with the question.