VB.net search button - sql

Question

I was working on this search button and I've manage to make it work. The only down side to this is when I try to search for a different item it keeps on putting back the old one I've searched for. What could be the problem?
Here's the code:
Private Sub btnSearch_Click(sender As Object, e As EventArgs) Handles btnSearch.Click
com.Connection = con
com.CommandText = ("Select Student_ID from Student where Student_ID = '" & txtSearch.Text & "'")
com.CommandText = "SELECT * FROM Student"
OpenDB()
Dim SurName As String = ""
Dim MiddleName As String = ""
Dim FirstName As String = ""
Dim SAddress As String = ""
Dim Birthday As String = ""
Dim Age As String = ""
Dim Birthplace As String = ""
Dim SContactNumber As String = ""
Dim GradeYear As String = ""
Dim SchoolYear As String = ""
Dim ParentGaurdian As String = ""
Dim PGContact As String = ""
Dim PGAddress As String = ""
rdr = com.ExecuteReader
If rdr.Read = True Then
SurName = rdr("StudentLastName").ToString
MiddleName = rdr("StudentMiddleName").ToString
FirstName = rdr("StudentFirstName").ToString
SAddress = rdr("StudentAddress").ToString
Birthday = rdr("Birthday").ToString
Age = rdr("Age").ToString
Birthplace = rdr("BirthPlace").ToString
SContactNumber = rdr("StudentContactNumber").ToString
GradeYear = rdr("GradeYearLevel").ToString
SchoolYear = rdr("SchoolYear").ToString
ParentGaurdian = rdr("ParentName").ToString
PGContact = rdr("ParentContactNumber").ToString
PGAddress = rdr("ParentAddress").ToString
End If
con.Close()
com.Dispose()
rdr.Close()
txtSurName.Text = SurName
txtMiddleName.Text = MiddleName
txtFirstName.Text = FirstName
txtSAddress.Text = SAddress
txtBirthday.Text = Birthday
txtAge.Text = Age
txtBirthplace.Text = Birthplace
txtSContactNumber.Text = SContactNumber
txtGradeYear.Text = GradeYear
txtSchoolYear.Text = SchoolYear
txtParentGaurdian.Text = ParentGaurdian
txtPGContact.Text = PGContact
txtPGAddress.Text = PGAddress
End Sub
I've tried to play around with the rdr.close because I think that's the thing I've placed wrong.

Answer 1

Looks like your SQL query should be more like this:
'com.CommandText = ("Select Student_ID from Student where Student_ID = '" & txtSearch.Text & "'")
'com.CommandText = "SELECT * FROM Student"
com.CommandText = "SELECT * FROM Student WHERE Student_ID = '" & txtSearch.Text & "'"

Answer 2

Remove below two lines..
com.CommandText = ("Select Student_ID from Student where Student_ID = '" & txtSearch.Text & "'")
com.CommandText = "SELECT * FROM Student"
And instead use below..
com.CommandText = ("Select Student_ID from Student where Student_ID = #searchText")
com.Parameters.AddWithValue("#searchText", txtSearch.Text)