在c#中存储和检索Access数据库中的图像

本文关键字:数据库 Access 图像 存储 检索 | 更新日期: 2023-09-27 18:01:33

我是c#编程新手,我正在尝试创建一个软件,允许用户将信息和图片保存到Ms access数据库中。我遵循了youtube上的教程,并设法存储了我需要的信息和图片,但我似乎无法检索图像并将其显示在图片框中。有人能帮我吗?

我的代码是:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.OleDb;
using System.IO;
namespace ConnectionApp
{
    public partial class ClinicaPrivada : Form
    {
        OleDbConnection DBConnection = new OleDbConnection();
        OleDbDataAdapter DataAdapter;
        DataTable LocalDatatable = new DataTable();
        int rowPosition = 0;
        int rowNumber = 0;

        public ClinicaPrivada()
        {
            InitializeComponent();
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            ConnectToDatabase();     
        }
        public void ConnectToDatabase()
        {
            DBConnection.ConnectionString = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=ClinicaPrivada.mdb";
            DataAdapter = new OleDbDataAdapter("Select * From Pacientes", DBConnection);
            DataAdapter.Fill(LocalDatatable);
            if (LocalDatatable.Rows.Count != 0)
            {
                rowPosition = LocalDatatable.Rows.Count;
            }
        }
        public void RefreshDBConnection()
        {
            if (DBConnection.State.Equals(ConnectionState.Open))
            {
                DBConnection.Close();
                LocalDatatable.Clear();
                ConnectToDatabase();
            }
        }
        private void btnBrowse_Click(object sender, EventArgs e)
        {
        }
        public byte[] ConvertAndStoreToDB(Image InputImage)
        {
            Bitmap BmpImage = new Bitmap(InputImage);
            MemoryStream Mystream = new MemoryStream();
            BmpImage.Save(Mystream, System.Drawing.Imaging.ImageFormat.Jpeg);
            byte[] ImageAsBytes = Mystream.ToArray();
            return ImageAsBytes;
        }
        public void StoreToDB(byte[] ImageAsBytes)
        {
            string NrDoPaciente;
            NrDoPaciente = Convert.ToString(txtNrdoPaciente.Text);
            string Empresa;
            Empresa = Convert.ToString(txtEmpresa.Text);
            string DataDaConsutla;
            DataDaConsutla = Convert.ToString(txtDatadaConsulta.Text);
            if (DBConnection.State.Equals(ConnectionState.Closed))
                DBConnection.Open();
            try
            {
                MessageBox.Show("Saving Image at index:" + rowPosition.ToString());
                OleDbCommand insert = new OleDbCommand("Insert Into Pacientes (NrDoPaciente, Empresa, DatadaConsulta, Document) VALUES('" + NrDoPaciente +"','" + Empresa + "','" + DataDaConsutla + "','" + "Document"  + "')" , DBConnection);
                OleDbParameter InsertParameter = insert.Parameters.AddWithValue("Docu", SqlDbType.Binary);
                int rowsAffected = insert.ExecuteNonQuery();
                MessageBox.Show("Data Stored successfully in " + rowsAffected.ToString() + "Row");
                rowPosition++;
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message.ToString());
                MessageBox.Show(ex.StackTrace.ToString());
            }
            finally
            {
                RefreshDBConnection();
            }
        }
        private Image ReadImageFromDB()
        {
            Image FetchedImg;
            if (rowNumber >= 0)
            {
                byte[] FetchedImgBytes = (byte[])LocalDatatable.Rows[rowNumber]["Document"];
                MemoryStream stream = new MemoryStream(FetchedImgBytes);
                FetchedImg = Image.FromStream(stream);
                return FetchedImg;
            }
            else
            {
                MessageBox.Show("There are no Images in the database yet. Please reconnect or add some images.");
                return null;
            }
        }
        private void btnBrowse_Click_1(object sender, EventArgs e)
        {
            if (openFileDialog1.ShowDialog() == DialogResult.OK)
            {
                pictureBox1.Image = Image.FromFile(openFileDialog1.FileName);
            }
        }
        private void btnSave_Click_1(object sender, EventArgs e)
        {
            StoreToDB(ConvertAndStoreToDB(pictureBox1.Image));
        }
        private void btnDisplayAll_Click(object sender, EventArgs e)
        {
            RefreshDBConnection();
            rowNumber = 0;
            pictureBox2.Image = ReadImageFromDB();
            btnNext.Enabled = true;
            BtnPrevious.Enabled = true; 
        }


    }
}

在c#中存储和检索Access数据库中的图像

创建如下数据表:表:Id int,图像OLE对象

然后使用下面的代码插入

//Convert img into bytes
byte[] FileBytes = null;
string imgpath = "PatientsPhotos/" + lbl_patientID.Content.ToString() + ".jpg";
FileStream fs = new FileStream(imgpath,System.IO.FileMode.Open,System.IO.FileAccess.Read);
BinaryReader BR = new BinaryReader(fs);
long allbytes = new FileInfo(imgpath).Length;
FileBytes = BR.ReadBytes((Int32)allbytes);
patient.imagepath = FileBytes;

然后,将'imagepath'插入到Image place表

和从表中检索imagepath并转换为图像,如下所示:

ImageSourceConverter imgConv = new ImageSourceConverter();
string path = ("PatientsPhotos/" + this.pt_id + ".jpg");
ImageSource imageSource = (ImageSource)imgConv.ConvertFromString(path);
imgVideo.Source = imageSource;

我想这可能对你有帮助。谢谢你

内存中的图像可能超出范围。如果我是对的,这个问题是直接相关的。

必须对图像进行复制。否则,您的图像将链接到创建它的对象,当该对象超出作用域时,您的图像数据将丢失。

我希望你从你正在尝试做的事情中得到异常。

顺便说一句,我同意那个建议避免使用MS Access的评论者的意见。