DataTable not updating Database with DataAdapter (VB.NET) - sql-server

Question

*NOTE: I deleted my previous question "Update Database from DataTable and DataAdapter" in place of this one. I have updated the wording and code to be what I am currently testing.
I am trying to update a database with info from a WinForm. I had no issues when using a “normal” SQL update command written by hand (parameters set to the text box values,) but I am trying to clean up and reduce my code and I thought I would bind the controls to a DataTable and use a DataAdapter's update command to achieve the same thing.
I have tried to get various combinations of setting parameters and update commands to work, but the Database is not getting updated from the new DataTable values. I have stepped through the code with each change and can see that the DataTable is getting the new textbox values, but those updates aren’t going to the Database. (This is seen when the Fill_Date block runs and selects all new data from the database.)
Things I’ve tried: Letting the binding get the new values vs. setting the parameters manually. Using the command builder to build the update command, using the .UpdateCommand.ExecuteNonQuery(), command and of course a straight.Update(DataTable) command.
Below is the code that I am using. I am hoping someone can tell me what it is I am doing wrong/missing, or what is the correct path to take. Is there a "best practice" or a better way to do this?
Public Class frmDATA
Dim dt_Test As New DataTable
Dim da_Test As New SqlDataAdapter
Dim SQLcmd As SqlCommand
Private Sub frmDemog_Load(sender As Object, e As EventArgs) Handles MyBase.Load
BuildSQL()
Fill_Data()
BindControls()
End Sub
Private Sub frmDemog_Closed(sender As Object, e As EventArgs) Handles Me.Closed
If Not IsNothing(dt_Test) Then dt_Test.Dispose()
If Not IsNothing(da_Test) Then da_Test.Dispose()
If Not IsNothing(SQLcmd) Then SQLcmd.Dispose()
Me.Dispose()
End Sub
Private Sub btnUpdate_Click(sender As Object, e As EventArgs) Handles btnUpdate.Click
Update_Me()
End Sub
Private Sub BindControls()
txtLName.DataBindings.Add("Text", dt_Test, "Last_Name")
txtFName.DataBindings.Add("Text", dt_Test, "First_Name")
txtAKA.DataBindings.Add("Text", dt_Test, "AKA")
End Sub
Public Sub Update_Me(RefreshSearch As Boolean, RefreshView As Boolean)
Try
Dim testID As Integer = frmTest.dgvSearch.CurrentRow.Cells(0).Value
da_Test.UpdateCommand.Parameters("#ID").Value = testID
da_Test.Update(dt_Test)
Fill_Data()
Catch SqlExceptionErr As SqlException
MsgBox(SqlExceptionErr.Message, vbCritical, "Error")
Catch ex As Exception
MsgBox(ex.Message, vbCritical, "Error")
End Try
End Sub
Public Sub Fill_Data()
Try
dt_Test.Clear()
da_Test.SelectCommand.Parameters("#ID").Value = testID
da_Test.Fill(dt_Test)
Catch SqlExceptionErr As SqlException
MsgBox(SqlExceptionErr.Message, vbCritical, "Error")
Catch ex As Exception
MsgBox(ex.Message, vbCritical, "Error")
End Try
End Sub
Private Sub BuildSQL()
'** Build Selection Query
SQLcmd = New SqlCommand(String.Join(Environment.NewLine,
"SELECT ",
"data_Test.[Last_Name], ",
"data_Test.[First_Name], ",
"data_Test1.[Last_Name] + ', ' + data_Test1.[First_Name] as [AKA] ",
"FROM [DB].data_Test ",
"LEFT JOIN [DB].data_Test as data_Test1 ",
"ON data_Test.[ID] = data_Test1.[AKA_Demog_ID] ",
"WHERE data_Test.[ID]=#ID"
), Vars.sqlConnDB)
SQLcmd.Parameters.Add("#ID", SqlDbType.Int)
da_Test.SelectCommand = SQLcmd
'** Build Update Query
SQLcmd = New SqlCommand(String.Join(Environment.NewLine,
"UPDATE [DB].data_Test SET ",
"[Last_Name] = #LName,",
"[First_Name] = #FName",
"WHERE [ID] = #ID"
), Vars.sqlConnDB)
With SQLcmd.Parameters
.Add("#LName", SqlDbType.NVarChar, 255, "Last_Name") 'Required
.Add("#FName", SqlDbType.NVarChar, 255, "First_Name") 'Required
.Add("#ID", SqlDbType.Int, 0, "ID")
End With
da_Test.UpdateCommand = SQLcmd
End Sub
End Class