在vb.net中更新SQL语句

Question

I am new in VB.NET and as well as SQL. I want to update records in my database. I made a dummy in my database.

Example the values are: ID = 1, name=Cath, age=21

In my interface made in VB.NET, I update the values example : name = txtName.Text and age = txtAge.Text where ID = 1. This is in my main form. In my main form, I have "view" button informing that by clicking that button, new form would pop up and would view the updated values by the user. The program does not have any errors except that when I want to update again the values in my SQL, It record BUT when I click "view" button again, It will show the previous inputted by the user (the first update upon running the interface). What should be the solution?

This is my code:

Mainform:

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

    SQLConnection.ConnectionString = ServerString
    Try
        If SQLConnection.State = ConnectionState.Closed Then
            SQLConnection.Open()
            MessageBox.Show("Successful connection")
        Else
            'SQLConnection.Close()
            MessageBox.Show("Connection is closed")
        End If
    Catch ex As Exception
        MsgBox(ex.ToString)

    End Try

End Sub

 Public Sub SaveNames(ByRef SQLStatement As String)
    Dim cmd As MySqlCommand = New MySqlCommand
 With cmd
        .CommandText = SQLStatement
        .CommandType = CommandType.Text
        .Connection = SQLConnection
        .ExecuteNonQuery()
    End With

    MsgBox("Successfully Added!")

End Sub

 Private Sub cmdSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdSave.Click
    Dim date_now As String

    date_now = Format(dtpDate.Value, "yyyy-MM-dd")

    Dim SQLStatement As String = "UPDATE people SET name='" & txtName.Text & "', date ='" & date_now & "'  WHERE 1"
    SaveNames(SQLStatement)
End Sub

Form 2: (where the updated data would be viewed)

 Private Sub Form2_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

    SQLConnection.ConnectionString = ServerString
    Try
        If SQLConnection.State = ConnectionState.Closed Then
            SQLConnection.Open()
            '====retrieve / update values in database=============
            Dim SQLStatement As String = "SELECT name, date FROM people"
            ViewInfos(SQLStatement)
        Else
            'SQLConnection.Close()
            MessageBox.Show("Connection is closed")
        End If
    Catch ex As Exception
        MsgBox(ex.ToString)

    End Try
End Sub

 Public Sub ViewInfos(ByRef SQLStatement As String)
    Dim cmd As MySqlCommand = New MySqlCommand

    With cmd
        .CommandText = SQLStatement
        .CommandType = CommandType.Text
        .Connection = SQLConnection
        .ExecuteNonQuery()

    End With
    '--read the records in database in phpmyadmin gui---
    Dim myReader As MySqlDataReader = cmd.ExecuteReader

    If myReader.Read Then
        lblName.Text = myReader.GetString(0)
        lblDate.Text = myReader.GetString(1)

    End If

    myReader.Close()
    MsgBox("Records Successfully Retrieved")

End Sub

Any help would be appreciated. Thanks!

Answer 1

更新sql时，连接字符串保持打开状态，因此当您尝试检索数据时，条件会关闭连接而不读取数据或更新文本框。

Answer 2

Take out the .ExecuteNonQuery() from the ViewInfos() method.

Refer to your forms via variables not via the form name:

Dim myForm as New Form2()
myForm.Show()