Visual Basic 添加行函数在重置函数后不起作用

Question

我会澄清我的问题。这是背景：

在 Visual Studio 2019 年使用 Visual Basic 创建数据库数据库由我必须考虑的设备和序列号等列表组成我有搜索功能，过滤功能，还有一些编辑功能

我遇到的问题是，一旦我单击重置按钮（应该将 dataviewgrid 未保存的更改重置回上次保存的更改），添加行功能就不再有效。代码没有抛出错误，只是在单击按钮时拒绝添加新行（在点击重置按钮之前，添加行按钮工作正常）

下面是我如何使用 sql:

填充我的数据库

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    Dim connection As New SqlConnection("Connection String Placeholder")
    Dim Table As New DataTable()
    Dim Adapter As New SqlDataAdapter("SELECT * FROM TrackMain$", connection)
    Adapter.Fill(Table)
    DataGridView1.DataSource = Table

    bind_data()
    nextId = Convert.ToInt32(dt.Rows(dt.Rows.Count - 1)(0)) + 1

End Sub

我还尝试对我的第一列进行数字排序，因此我在那里和我的添加行函数中也有 NextID 值（这可能是罪魁祸首）

这里是添加行然后重置函数：

Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
    Dim dr As DataRow = dt.NewRow()
    dr(0) = nextId
    dt.Rows.Add(dr)
    nextId += 1

End Sub

Private Sub Button6_Click(sender As Object, e As EventArgs) Handles Button6.Click
    Dim connection As New SqlConnection("Connection String Placeholder")
    Dim Table As New DataTable()
    Dim Adapter As New SqlDataAdapter("SELECT * FROM TrackMain$", connection)
    Adapter.Fill(Table)
    DataGridView1.DataSource = Table
    nextId = Convert.ToInt32(dt.Rows(dt.Rows.Count - 1)(0)) + 1
End Sub

如有任何问题，请告诉我，谢谢

编辑：这是我的 bind_data() Sub

Private Sub bind_data()
    connection.Open()
    Dim cmdTxt As String = "SELECT * FROM TrackMain$"
    da = New SqlDataAdapter(New SqlCommand(cmdTxt, connection))
    Dim builder As SqlCommandBuilder = New SqlCommandBuilder(da)
    da.Fill(dt)
    Dim source As BindingSource = New BindingSource With {
                                .DataSource = dt
                              }
    DataGridView1.DataSource = source

End Sub

Answer 1

这是我测试的全部代码，代码对我有用。

Private dt As DataTable = New DataTable
Private da As SqlDataAdapter
Private connection As SqlConnection = New SqlConnection("connection string")
Dim nextId As Integer = 0

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    bind_data()
    nextId = Convert.ToInt32(dt.Rows(dt.Rows.Count - 1)(0)) + 1
End Sub

' Update database by DataGridView.'
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    For i As Integer = DataGridView1.Rows.Count - 1 To 0
        Dim row As DataGridViewRow = DataGridView1.Rows(i)

        If Not row.IsNewRow AndAlso row.Cells(0).Value Is Nothing Then
            DataGridView1.Rows.RemoveAt(i)
        End If
    Next
    DataGridView1.EndEdit()
    da.Update(dt)
End Sub

' Add new Row.'
Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
    Dim dr As DataRow = dt.NewRow()
    dr(0) = nextId
    dt.Rows.Add(nextId)
    nextId += 1
End Sub

' Reset the dt and DataGridView.'
Private Sub Button4_Click(sender As Object, e As EventArgs) Handles Button4.Click
    Dim Table As New DataTable()
    dt.Clear()
    Dim Adapter As New SqlDataAdapter("SELECT * FROM TrueTrack", connection)
    Adapter.Fill(dt)
    DataGridView1.DataSource = dt
    nextId = Convert.ToInt32(dt.Rows(dt.Rows.Count - 1)(0)) + 1
End Sub

Private Sub bind_data()
    connection.Open()
    Dim cmdTxt As String = "SELECT * FROM TrueTrack"
    da = New SqlDataAdapter(New SqlCommand(cmdTxt, connection))
    Dim builder As SqlCommandBuilder = New SqlCommandBuilder(da)
    da.Fill(dt)
    Dim source As BindingSource = New BindingSource With {
                                    .DataSource = dt
                                  }
    DataGridView1.DataSource = source
End Sub
Private Sub Form1_FormClosing(sender As Object, e As FormClosingEventArgs) Handles MyBase.FormClosing
    connection.Close()
End Sub

编辑：数据库设计（取消auto-Increment of 'Id'）：

DataGridView按'Id'排序可参考以下代码。

Private Sub Button5_Click(sender As Object, e As EventArgs) Handles Button5.Click
    Me.DataGridView1.Sort(Me.DataGridView1.Columns("Id"), ListSortDirection.Ascending)
End Sub

然后更改代码以删除 DataGridView 行。

Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
    If DataGridView1.Rows.Count > DataGridView1.CurrentCell.RowIndex + 1 Then
        DataGridView1.Rows.RemoveAt(DataGridView1.CurrentCell.RowIndex)
    End If
    nextId = Convert.ToInt32(DataGridView1.Rows(DataGridView1.CurrentCell.RowIndex).Cells(0).Value) + 1
End Sub

Visual Basic 添加行函数在重置函数后不起作用

Visual Basic Add Row Function Not Working After Reset Function

sql

database

vb.net

visual-studio

visual-studio-2019