實現功能如下圖：
注明：此文使用的是DevExpress控件，winform 原生控件也是一樣使用方法。
1.點擊選擇圖片按鈕，功能為通過對話框選擇要上傳的文件，並將該文件在下面的PictureEdit中顯示出來。具體代碼如下：
private void btnChoosePic_Click(object sender, EventArgs e) { ShowPic(pictureEdit1); } /// <summary> /// 選擇圖片 /// </summary> /// <param name="picEdit"></param> public static void ShowPic(PictureEdit picEdit) { OpenFileDialog ofd = new OpenFileDialog(); ofd.InitialDirectory = @"C:\"; ofd.Filter = "Image Files(*.JPG;*.PNG;*.jpeg;*.GIF;*.BMP)|*.JPG;*.PNG;*.GIF;*.BMP;*.jpeg|All files(*.*)|*.*"; ofd.RestoreDirectory = true; if (ofd.ShowDialog() == DialogResult.OK) { PicAddress = ofd.FileName; Image imge = Image.FromFile(PicAddress); Bitmap bm = new Bitmap(imge, picEdit.Width, picEdit.Height); picEdit.Image = bm; } }ShowPic()方法為靜態方法，可以直接調用，其中的PicAddress變量為靜態全局變量，用於記錄要上傳文件的文件地址。PictureEdit顯示圖片的方式，是通過PictureEdit的image屬性設定的，將圖片轉成Bitmap格式，位圖文件是最簡單的圖片格式。
2.上傳圖片，該按鈕的功能是將選定的圖片上傳到數據庫中，具體的實現代碼如下：
/// <summary> /// 上傳圖片 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void btnUploadPic_Click(object sender, EventArgs e) { if (PicAddress != null) { if (PicType.Equals("教師")) { var sqlSearch = $@"select count(*) from studentmanager.picture where PicTypeId = '{TeacherId}' and PicType='{PicType}'"; var dsSearch = _db.GetResult(sqlSearch); if (dsSearch.Tables[0].Rows[0][0].ToString().Equals("0")) //沒有重復的，則進行新增插入操作 { byte[] pic = CommonFunction.GetContent(PicAddress); var result = _db.SavePictureToDB(pic, PicAddress, PicType, TeacherId); if (result > 0) { CommonFunction.MessageShow("頭像添加成功", "提示", "OK", "Information"); DialogResult = DialogResult.OK; } else { CommonFunction.MessageShow("頭像添加失敗"); } } else { //更新頭像 if (PicAddress.Equals(String.Empty)) { CommonFunction.MessageShow("沒有重新選擇圖片進行更新"); return; } byte[] pic = CommonFunction.GetContent(PicAddress); var result = _db.UpdatePictureToDb(pic, PicAddress, PicType, TeacherId); if (result > 0) { CommonFunction.MessageShow("頭像更新成功", "提示", "OK", "Information"); DialogResult = DialogResult.OK; } else { CommonFunction.MessageShow("頭像更新失敗"); } } } else if(PicType.Equals("學生")) { var sqlSearch = $@"select count(*) from studentmanager.picture where PicTypeId = '{StudentId}' and PicType='{PicType}'"; var dsSearch = _db.GetResult(sqlSearch); if (dsSearch.Tables[0].Rows[0][0].ToString().Equals("0")) //沒有重復的，則進行新增插入操作 { byte[] pic = CommonFunction.GetContent(PicAddress); var result = _db.SavePictureToDB(pic, PicAddress, PicType, StudentId); if (result > 0) { CommonFunction.MessageShow("頭像添加成功", "提示", "OK", "Information"); DialogResult = DialogResult.OK; } else { CommonFunction.MessageShow("頭像添加失敗"); } } else { //更新頭像 if (PicAddress.Equals(String.Empty)) { CommonFunction.MessageShow("沒有重新選擇圖片進行更新"); return; } byte[] pic = CommonFunction.GetContent(PicAddress); var result = _db.UpdatePictureToDb(pic, PicAddress, PicType, StudentId); if (result > 0) { CommonFunction.MessageShow("頭像更新成功", "提示", "OK", "Information"); DialogResult = DialogResult.OK; } else { CommonFunction.MessageShow("頭像更新失敗"); } } } } else { CommonFunction.MessageShow("請先選擇圖片！", "提示", "OK", "Error"); } }上傳的過程大概就是：根據文件地址將對應文件轉換成數據流二進制格式–>編寫對應的SQL語句–>執行該SQL語句，將圖片添加到數據庫中。
上面代碼中SavePictureToDB方法代碼如下：
/// <summary> /// 保存圖片到數據庫 /// </summary> /// <param name="imageByte"></param> /// <param name="Tablename"></param> /// <param name="FieldPicturename"></param> /// <param name="FieldIdxname"></param> /// <param name="FieldIdxvalue"></param> /// <returns></returns> public int SavePictureToDB(byte[] imageByte, string Picturename, string PicType, int PicTypeId) { var result = 0; try { if (imageByte != null && imageByte.Length != 0) { using (var conn = new MySqlConnection()) { conn.ConnectionString = ConnectionString; conn.Open(); var insertStr = @"INSERT INTO studentmanager.picture ( Picturename, PicType, PicTypeId, imageByte ) VALUES ( @Picturename, @PicType, @PicTypeId, @imageByte );"; var comm = new MySqlCommand(); comm.Connection = conn; comm.CommandText = insertStr; comm.CommandType = CommandType.Text; //設置數據庫字段類型MediumBlob的值為圖片字節數組imageByte comm.Parameters.Add(new MySqlParameter("@imageByte", MySqlDbType.MediumBlob)).Value = imageByte; comm.Parameters.Add(new MySqlParameter("@Picturename", MySqlDbType.VarChar)).Value = Picturename; comm.Parameters.Add(new MySqlParameter("@PicType", MySqlDbType.VarChar)).Value = PicType; comm.Parameters.Add(new MySqlParameter("@PicTypeId", MySqlDbType.Int32)).Value = PicTypeId; //execute sql result = comm.ExecuteNonQuery(); comm.Dispose(); conn.Close(); conn.Dispose(); } } } catch (Exception) { // throw ex; } return result; }3.加載圖片顯示到PictureEdit；
/// <summary> /// 窗口加載 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void HeadManager_Load(object sender, EventArgs e) { LoadImage(PicType, PicType.Equals("教師") ? TeacherId : StudentId); } /// <summary> /// 獲取圖片 /// </summary> /// <param name="picType"></param> /// <param name="picTypeid"></param> private void LoadImage(string picType, int picTypeid) { try { var imageBytes = _db.GetImage(picType, picTypeid); var image = CommonFunction.GetImageByBytes(imageBytes); Bitmap bm = new Bitmap(image, pictureEdit1.Width, pictureEdit1.Height); pictureEdit1.Image = bm; } catch (Exception) { pictureEdit1.Image = Resource.DefaultUser; } }4.用到的公共方法：
/// <summary> /// 轉換為Byte[] /// </summary> /// <param name="filepath"></param> /// <returns></returns> public static byte[] GetContent(string filepath)//將指定路徑下的文件轉換成二進制代碼，用於傳輸到數據庫 { FileStream fs = new FileStream(filepath, FileMode.Open, FileAccess.Read); byte[] byData = new byte[fs.Length];//新建用於保存文件流的字節數組 fs.Read(byData, 0, byData.Length);//讀取文件流 fs.Close(); return byData; } /// <summary> /// 讀取byte[]並轉化為圖片 /// </summary> /// <param name="bytes">byte[]</param> /// <returns>Image</returns> public static Image GetImageByBytes(byte[] bytes) { Image photo; using (MemoryStream ms = new MemoryStream(bytes)) { ms.Write(bytes, 0, bytes.Length); photo = Image.FromStream(ms, true); ms.Dispose(); ms.Close(); } return photo; }