Question

我是新手，我正试图在.vb中使用Visual Studio 2013创建应用程序这个应用程序适用于使用SQl SERVER EXPRESS女士制作的本地数据库（书籍，Cd，Dvd等），我想知道我是否可以通过APP重新加载DatagridView和我的数据集。使用App将列添加到我的数据库。事实上，我试图找到一种方法在我的数据网格视图中显示这个新列，我不想总是在VS中，因为我想在小型笔记本电脑上使用我的应用程序。

好吧，我不知道从哪里开始，所以我试过这个：

Imports System.Data.SqlClient
...
Private Sub Form8_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    Dim cn As New SqlConnection("Data Source=PC-ME\SQLEXPRESS;Initial Catalog=Database;Integrated Security=True")
    Dim cmd As SqlCommand = cn.CreateCommand()
    cmd.CommandText = "Select * FROM CONSULTE"
    Dim adapter As New SqlDataAdapter()
    Dim ds As New DataSet()
    adapter.SelectCommand = cmd
    cn.Open()
    adapter.Fill(ds, "CONSULTE")
    cn.Close()
    CONSULTEDataGridView.DataSource = ds
    CONSULTEDataGridView.DataMember = "CONSULTE"

End Sub

但它确实有效。

我的窗口可以在哪里形成ALTER TABLE：

Imports System.Data.SqlClient
Public Class Form7
Dim cn As New SqlConnection("Data Source=PC-ME\SQLEXPRESS;Initial Catalog=Database;Integrated Security=True")
Dim cmd As New SqlCommand
Dim dr As SqlDataReader

Private Sub Form7_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    cmd.Connection = cn
End Sub

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    If table.Text <> "" And colonne.Text <> "" And typede.Text <> "" Then
        cn.Open()
        cmd.CommandText = "ALTER TABLE " & table.Text & " ADD " & colonne.Text & " " & typede.Text & ""
        cmd.ExecuteNonQuery()
        cn.Close()
        table.Text = ""
        colonne.Text = ""
        typede.Text = ""
    Else
        MsgBox("Vous devez remplir les trois champs!")
    End If
End Sub

Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
    If table.Text <> "" And colonne.Text <> "" Then
        cn.Open()
        cmd.CommandText = "ALTER TABLE " & table.Text & " DROP COLUMN " & colonne.Text & ""
        cmd.ExecuteNonQuery()
        cn.Close()
        table.Text = ""
        colonne.Text = ""
    Else
        MsgBox("Vous devez remplir correctement les deux premiers champs!")
    End If
End Sub
End Class

谢谢你的帮助！

PS：对不起我的英语，这不是我的母语。

Answer 1

我不是专业人士，但想尝试一下。我使用了 WithEvents 语句。

请尝试以下代码。我假设你正在以两种形式编写代码吗？ Form7 和表单8

在表格7中，执行此操作

Imports System.Data.SqlClient
Public Class Form7
 ...
 Public Event LoadDataGridView(sender As System.Object)

Private Sub Form7_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    cmd.Connection = cn
End Sub

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    If table.Text <> "" And colonne.Text <> "" And typede.Text <> "" Then
      --- Your stuff here. After completion of code, following event will be raised

      RaiseEvent LoadDataGridView(sender)
    Else
        MsgBox("Vous devez remplir les trois champs!")
    End If
End Sub

Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
    If table.Text <> "" And colonne.Text <> "" Then
      -- Your stuff here. After completion of code, following event will be raised


      RaiseEvent LoadDataGridView(sender)
    Else
        MsgBox("Vous devez remplir correctement les deux premiers champs!")
    End If
End Sub
End Class

现在，在表格8中，执行此操作

Imports System.Data.SqlClient
Public Class Form8
Private WithEvents form7 As New Form7

Private Sub Form8_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    -- You stuff
End Sub

Private Sub form7_LoadDataGridView(sender As Object) Handles form7.LoadDataGridView
 'Call load procedure to reload datagridview
 Form8_Load(Nothing,Nothing)
End Sub
End Class

Answer 2

所以我找到了办法！如果有人想知道，这是一个例子： Datagridview1是我在form1

上的datagridview的名称

表格1：

Imports System.Data.SqlClient
Public Class Form1

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    Dim cn As New SqlConnection("Data Source=PC-ME\SQLEXPRESS;Initial Catalog=BDD;Integrated Security=True")
    cn.Open()
    Dim cmd As SqlCommand = cn.CreateCommand()
    Dim adapter As New SqlDataAdapter()
    Dim ds As New DataSet()
    Dim sql As String

    sql = "SELECT * FROM CONSULTE"
    adapter.SelectCommand = New SqlCommand(sql, cn)
    adapter.Fill(ds)
    DataGridView1.DataSource = ds.Tables(0)

End Sub
End Class

表单3，我可以在其中添加或删除列：

Imports System.Data.SqlClient
Public Class Form3
Dim cn As New SqlConnection("Data Source=PC-ME\SQLEXPRESS;Initial Catalog=BDD;Integrated Security=True")
Dim cmd As New SqlCommand
Dim dr As SqlDataReader

Private Sub Form3_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    cmd.Connection = cn
End Sub

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    If table.Text <> "" And colonne.Text <> "" And typede.Text <> "" Then
        cn.Open()
        cmd.CommandText = "ALTER TABLE " & table.Text & " ADD " & colonne.Text & " " & typede.Text & ""
        cmd.ExecuteNonQuery()
        cn.Close()
        table.Text = ""
        colonne.Text = ""
        typede.Text = ""
    Else
        MsgBox("Vous devez remplir les trois champs!")
    End If
End Sub

Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
    If table.Text <> "" And colonne.Text <> "" Then
        cn.Open()
        cmd.CommandText = "ALTER TABLE " & table.Text & " DROP COLUMN " & colonne.Text & ""
        cmd.ExecuteNonQuery()
        cn.Close()
        table.Text = ""
        colonne.Text = ""
    Else
        MsgBox("Vous devez remplir correctement les deux premiers champs!")
    End If
End Sub
End Class

其中“table”（= Table），“colonne”（= Column）和“typede”（= type）是三个文本框的名称

Visual Studio：在数据库中发生结构更改时重新加载数据集和数据网格

2 个答案: