我试着去做一次登录系统中储存的凭证和所需的剖面图片上的图像一个access数据库。 所希望的结果是，当登入相匹配形式1的关闭和开形式2有所保存的图像装上一个角落。
我试图这样做
表1code:
Imports System.Data.OleDb
Imports System.IO
Public Class Form1
Private PictureFormat As String
Private Sub FillPictureBoxFromFile()
With OpenFileDialog1
.Filter = "(*.jpg)|*.jpg|(*.png)|*.png"
.RestoreDirectory = True
.Title = "Select a file to open"
If .ShowDialog = DialogResult.OK Then
PictureBox1.Image = Image.FromFile(OpenFileDialog1.FileName)
End If
PictureFormat = Path.GetExtension(OpenFileDialog1.FileName)
End With
End Sub
Private cnStr As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Users\geral\source\repos\Login Fase 3 Final\Login Fase 3 Final\bin\Release\DBLoginPic.mdb"
Private Sub saveimage()
Dim arrimage() As Byte
Using mstream As New System.IO.MemoryStream
If PictureFormat.ToLower = ".png" Then
PictureBox1.Image.Save(mstream, System.Drawing.Imaging.ImageFormat.Png)
ElseIf PictureFormat.ToLower = ".jpg" Then
PictureBox1.Image.Save(mstream, System.Drawing.Imaging.ImageFormat.Jpeg)
End If
arrimage = mstream.GetBuffer()
Dim Filesize As Long
Filesize = mstream.Length
End Using
Using con As New OleDbConnection(cnStr),
cmd As New OleDbCommand("Insert into TBLoginPic (Imagen) Values (@Imagen)", con)
With cmd
.Parameters.Add("@Imagen", OleDbType.Binary).Value = arrimage
'.Parameters.Add("@Nombre", OleDbType.VarChar).Value = TextBox1.Text
con.Open()
.ExecuteNonQuery()
End With
End Using
End Sub
Private Function GetDataByName(name As String) As DataTable
Dim dt As New DataTable
Using conn As New OleDb.OleDbConnection(cnStr),
cmd As New OleDbCommand("Select * from TBLoginPic where Usuario= @Buscar", conn)
cmd.Parameters.Add("@Buscar", OleDbType.VarChar).Value = TBusuario.Text
conn.Open()
Using reader = cmd.ExecuteReader
dt.Load(reader)
End Using
End Using
Return dt
End Function
Private Sub Label2_Click(sender As Object, e As EventArgs) Handles Label2.Click
End Sub
Private Sub TBusuario_TextChanged(sender As Object, e As EventArgs) Handles TBusuario.TextChanged
End Sub
Private Sub TBcontraseña_TextChanged(sender As Object, e As EventArgs) Handles TBcontraseña.TextChanged
End Sub
Private Sub BtnLoguearse_Click(sender As Object, e As EventArgs) Handles BtnLoguearse.Click
If Me.TBLoginPicTableAdapter.BuscarDatos(Me.DBLoginPicDataSet.TBLoginPic, TBusuario.Text, TBcontraseña.Text) Then
Dim dt As DataTable
Try
dt = GetDataByName(TBusuario.Text)
Catch ex As Exception
MessageBox.Show(ex.Message)
Exit Sub
End Try
TBusuario.Text = dt(0)("Usuario").ToString
Dim arrimage = DirectCast(dt(0)("Imagen"), Byte())
Dim mstream As New System.IO.MemoryStream(arrimage)
PictureBox1.Image = Image.FromStream(mstream)
Form2.Show()
_selectedImage = PictureBox1.Image
Me.Close()
Else
MsgBox("Datos Erroneos")
End If
End Sub
Private Sub BtnRegistrarse_Click(sender As Object, e As EventArgs) Handles BtnRegistrarse.Click
Me.TBLoginPicBindingSource.AddNew()
Me.TBLoginPicBindingSource.EndEdit()
Me.TBLoginPicTableAdapter.Update(Me.DBLoginPicDataSet)
Try
saveimage()
Catch ex As Exception
MessageBox.Show(ex.Message)
Exit Sub
End Try
MsgBox("Image has been saved in the database")
End Sub
Private Sub BtnExaminar_Click(sender As Object, e As EventArgs) Handles BtnExaminar.Click
FillPictureBoxFromFile()
End Sub
Private Sub PictureBox1_Click(sender As Object, e As EventArgs) Handles PictureBox1.Click
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
'TODO: This line of code loads data into the 'DBLoginPicDataSet.TBLoginPic' table. You can move, or remove it, as needed.
Me.TBLoginPicTableAdapter.Fill(Me.DBLoginPicDataSet.TBLoginPic)
End Sub
Private Sub TBLoginPicBindingNavigatorSaveItem_Click(sender As Object, e As EventArgs)
Me.Validate()
Me.TBLoginPicBindingSource.EndEdit()
Me.TableAdapterManager.UpdateAll(Me.DBLoginPicDataSet)
End Sub
End Class
表2码：
Module imagen
Public _selectedImage As Image
Public ReadOnly Property SelectedImage As Image
Get
Return _selectedImage
End Get
End Property
End Module
Public Class Form2
Private Sub TBLoginPicBindingNavigatorSaveItem_Click(sender As Object, e As EventArgs)
Me.Validate()
Me.TBLoginPicBindingSource.EndEdit()
Me.TableAdapterManager.UpdateAll(Me.DBLoginPicDataSet)
End Sub
Private Sub Form2_Load(sender As Object, e As EventArgs) Handles MyBase.Load
'TODO: This line of code loads data into the 'DBLoginPicDataSet.TBLoginPic' table. You can move, or remove it, as needed.
Me.TBLoginPicTableAdapter.Fill(Me.DBLoginPicDataSet.TBLoginPic)
_selectedImage = PBPerfil.Image
End Sub
Public Sub PBPerfil_Click(sender As Object, e As EventArgs) Handles PBPerfil.Click
End Sub
End Class
得到这个错误
系统。InvalidCastException:'无法投对象的类型系统。DBNull'type'系统。字节[]'.'
这是我的数据库看起来像(不要担心，没有任何个人的信息在这里))
任何提示什么我能做的更好？