从对象类型System.Drawing.Bitmap到已知的托管提供程序本机类型VB.NET不存在映射

Question

我有问题从PictureBox1保存图像到我的SQL服务器数据库，我做了我的研究，发现我必须将我的图像转换为字节数组，以便这样做，但我不知道如何应用它这个代码我正在尝试编辑。当我点击保存按钮时，我收到此错误：No mapping exists from object type System.Drawing.Bitmap to a known managed provider native type。

我认为这与将图像插入数据库有关，因此我将向您展示与其相关的代码片段。

这是具有其属性的类：

Friend Class PersonFile
    Private _NewID As String

 Private _PersonID As String
    Friend Property PersonID() As String
        Get
            Return _PersonID
        End Get
        Set(ByVal Value As String)
            _PersonID = Value
        End Set
    End Property
 Private _Photo As Image
    Friend Property Photo() As Image
        Get
            Return _Photo
        End Get
        Set(ByVal Value As Image)
            _Photo = Value
        End Set
    End Property

这是插入的功能：

Friend Class PersonFileDB
 Friend Function DXInsertFile(ByVal cItem As PersonFile) As PersonFile
        Dim cReturn As New PersonFile

 Using oleCON As New SqlConnection(AppVariables.GConnectionString)
            oleCON.Open()

 Dim n1 As String = ""
            n1 = CreateNewID()
            cItem.PersonID = n1

            Dim xSQL As New StringBuilder
            xSQL.AppendLine(" INSERT INTO PersonData ")
            xSQL.AppendLine("( ")
            xSQL.AppendLine(" PersonID, ")
            xSQL.AppendLine(" Photo, ")
            ''Other code...
            xSQL.AppendLine("VALUES ( ")
            xSQL.AppendLine(" @PersonID, ")
            xSQL.AppendLine(" @Photo, ")
            ''Other code...

            Dim oleComm As New SqlCommand(xSQL.ToString, oleCON)
            With oleComm.Parameters
                .AddWithValue(" @PersonID, ", cItem.PersonID)
                .AddWithValue("@Photo", cItem.Photo)
            ''Other code...
            End With

            Dim n As Integer
            n = oleComm.ExecuteNonQuery()
            If n <> 0 Then
                cItem.Updated = True
                SaveNewID(CInt(cItem.PersonID))
                cReturn = cItem
            End If
 End Using
 Return cReturn
End Function

这是点击事件：

Private CurrPerson As New PersonFile

Private Sub cmdPersonSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdPersonSave.Click

        CurrPerson.Photo = PictureBox1.Image
        ''Other code...
  Dim cdb As New PersonFileDB

        Select Case cmdPersonSave.Text
            Case "Add"
                UIClear()
                UISetControls(False)
                cmdPersonSave.Text = "Save"
                cmdPersonUpdate.Text = "Cancel"
                cmdPersonDelete.Enabled = False
                cmdSearch.Enabled = False
            Case "Save"
                If EditMode Then
                    CurrPerson = cdb.DXUpdateFile(CurrPerson)
                    EditMode = False
                Else
                    CurrPerson = cdb.DXInsertFile(CurrPerson)
                End If
                If CurrPerson.Updated Then
                    BindGrid(CurrPerson.PersonID)
                    UISetControls(True)
                End If
                cmdPersonSave.Text = "Add"
                cmdPersonUpdate.Text = "Edit"
                cmdPersonDelete.Enabled = True
                cmdSearch.Enabled = True
                UISetControls(True)
        End Select
        End Sub

Answer 1

在SQL SERVER数据库中有数据类型IMAGE。将列数据类型保持为IMAGE。

您可以使用以下示例代码并将Image传递给下面的函数，该函数将图像转换为字节以存储在数据库中。

public static byte[] ImageToByte2(Image img)
        {
            byte[] byteArray = new byte[0];
            using (MemoryStream stream = new MemoryStream())
            {
                img.Save(stream, System.Drawing.Imaging.ImageFormat.Png);
                stream.Close();

                byteArray = stream.ToArray();
            }
            return byteArray;
        }

Answer 2

您只需要定义名为“imgpath”的图像路径

//upload image

private void button1_Click_1(object sender, EventArgs e)
{
    OpenFileDialog opf = new OpenFileDialog();

    opf.Filter = "Choose Image(*.jpg; *.png; *.gif)|*.jpg; *.png; *.gif";
    if (opf.ShowDialog() == DialogResult.OK)
    {
        imgpath.Text = opf.FileName;
        pictureBox3.Image = Image.FromFile(opf.FileName);
    }
}
// ADD NEW/INSERT IMAGE TO DB
private void button5_Click(object sender, EventArgs e)
{
    string filepath = imgpath.Text;
    string filename = Path.GetFileName(imgpath.Text);
    FileStream fs = new FileStream(imgpath.Text, FileMode.Open, 
     FileAccess.Read);
    BinaryReader br = new BinaryReader(fs);
    Byte[] bytes = br.ReadBytes((Int32)fs.Length);
    br.Close();
    fs.Close();

    if (imgpath.Text != "")
    {
        cmd = new SqlCommand("insert into tbl_Record(@StudentImage)", con);
        con.Open();
        MemoryStream ms = new MemoryStream();

       // must use toolbox to add picturebox
        pictureBox3.Image.Save(ms, pictureBox3.Image.RawFormat);
        byte[] img = ms.ToArray();
        cmd.Parameters.Add("@StudentImage", SqlDbType.Binary).Value = 
       bytes;
        cmd.ExecuteNonQuery();
        con.Close();
        MessageBox.Show("Succeed");
        DisplayData();
        ClearData();
    }
    else
    {
        MessageBox.Show("Fill Required Informations!");
    }
}