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WPF MVVM+EF增删改查 简单示例(一)实现了对学生信息的管理。
现在需求发生变更,在录入学生资料的时候同时需要录入学生的图片信息，并且一名学生只能有一张图片资料。并可对学生的图片资料进行更新。
添加了那些功能，先看看效果图：
第一步:添加实体类StudentPhotoEntity.cs
public class StudentPhotoEntity
{
public int StudentId { get; set; }
public byte[] StudentPhoto { get; set; }
public virtual StudentEntity Student { get; set; }
}
第二步:修改实体类StudentEntity.cs
public class StudentEntity
{
public int StudentId { get; set; }
public string StudentName { get; set; }
public int StudentAge { get; set; }
public int StudentSex { get; set; }
public string StudentAddress { get; set; }
public virtual StudentPhotoEntity StudentPhoto { get; set; }
}
第三步:添加StudentPhotoEntityMapping.cs
public class StudentPhotoEntityMapping : EntityTypeConfiguration<StudentPhotoEntity>
{
public StudentPhotoEntityMapping()
{
this.HasKey(t => t.StudentId);
this.ToTable("StudentPhoto");
this.Property(t => t.StudentPhoto).HasColumnName("StudentPhoto").HasColumnType(SqlDbType.Image.ToString()).IsRequired();
}
}
第四步:修改StudentEntityMapping.cs
public class StudentEntityMapping : EntityTypeConfiguration<StudentEntity>
{
public StudentEntityMapping()
{
this.HasKey(t => t.StudentId);
this.ToTable("Student");
this.Property(t => t.StudentId).HasColumnName("StudentId").HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity).IsRequired();
this.Property(t => t.StudentName).HasColumnName("StudentName").HasColumnType(SqlDbType.NVarChar.ToString()).HasMaxLength(50).IsRequired();
this.Property(t => t.StudentAge).HasColumnName("StudentAge").HasColumnType(SqlDbType.Int.ToString()).IsRequired();
this.Property(t => t.StudentSex).HasColumnName("StudentSex").HasColumnType(SqlDbType.Int.ToString()).IsRequired();
this.Property(t => t.StudentAddress).HasColumnName("StudentAddress").HasColumnType(SqlDbType.NVarChar.ToString()).HasMaxLength(200).IsRequired();
this.HasRequired(t => t.StudentPhoto).WithRequiredPrincipal(i => i.Student);
this.HasOptional(t => t.StudentPhoto).WithRequired(i => i.Student);
}
}
第五步：更新数据库
1,将连接字符串修改为绝对路径
2,打开“程序包管理器控制台”
3,输入Add-Migration命令 回车
4,输入Name 回车
5,输入Update-Database 回车
6,修改链接字符串
第六步：修改StudentControl.xaml在DataGrid中添加列
<DataGridTemplateColumn Header="头像" Width="100" >
<DataGridTemplateColumn.CellTemplate>
<DataTemplate >
<Grid>
<Image Source="{Binding StudentPhoto.StudentPhoto,Converter={StaticResource convertImageAndByte}}" Stretch="Fill" Width="50" Height="50" HorizontalAlignment="Center" VerticalAlignment="Center" ></Image>
</Grid>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
第七步:修改AddOrEditWindow.xaml添加图片输入控件
<StackPanel Grid.Row="0" Grid.Column="1" Orientation="Horizontal" VerticalAlignment="Center" Margin="20,0,0,0">
<Border BorderThickness="0.6" BorderBrush="Black">
<Image x:Name="img" Width="70" Height="70" Stretch="Fill" Source="{Binding CurrentStudentEntity.StudentPhoto.StudentPhoto,Mode=TwoWay,Converter={StaticResource convertImageAndByte}}"></Image>
</Border>
<Button Width="40" Height="20" VerticalAlignment="Bottom" Margin="10,0,0,0" Content="浏览" Click="Button_Click"> </Button>
</StackPanel>
第八步:修改AddOrEditViewModel.cs中的Save()方法
private void Save()
{
StudentEntity student = new StudentEntity()
{
StudentName = CurrentStudentEntity.StudentName,
StudentAge = CurrentStudentEntity.StudentAge,
StudentSex = IsChecked ? 0 : 1,
StudentAddress = CurrentStudentEntity.StudentAddress,
StudentPhoto = new StudentPhotoEntity()
{
StudentPhoto = CurrentStudentEntity.StudentPhoto.StudentPhoto
}
};
if (IsAdd)
{
StudentDal.Insert(student);
}
else
{
student.StudentId = CurrentStudentEntity.StudentId;
student.StudentPhoto.StudentId = CurrentStudentEntity.StudentId;
StudentDal.Update(student);
}
}
第九步:添加一个转换器类，实现图片与byte[]的相互转化
[System.Windows.Data.ValueConversion(typeof(byte[]), typeof(ImageSource))]
public class ConvertImageAndByte : System.Windows.Data.IValueConverter
{
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
byte[] binaryimagedata = value as byte[];
if (binaryimagedata == null) return "";
using (Stream imageStreamSource = new MemoryStream(binaryimagedata, false))
{
JpegBitmapDecoder jpeDecoder = new JpegBitmapDecoder(imageStreamSource, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.OnLoad);
ImageSource imageSource = jpeDecoder.Frames[0];
return imageSource;
}
}
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
if (value == null)
return "";
string path = value.ToString().Substring(8, value.ToString().Length - 8);
System.Drawing.Bitmap bitmap;
BitmapSource bmp = new BitmapImage(new Uri(path, UriKind.Absolute));
using (MemoryStream outStream = new MemoryStream())
{
BitmapEncoder enc = new BmpBitmapEncoder();
enc.Frames.Add(BitmapFrame.Create(bmp));
enc.Save(outStream);
bitmap = new System.Drawing.Bitmap(outStream);
}
System.Drawing.Bitmap bm = new System.Drawing.Bitmap(bitmap);
System.IO.MemoryStream stream = new System.IO.MemoryStream();
bm.Save(stream, System.Drawing.Imaging.ImageFormat.Jpeg);
byte[] imgBytes = stream.ToArray();
stream.Close();
return imgBytes;
}
}
此文仅作学习中的记录，希望对看到此文的同学有一点点的帮助。
文中如果有不正确的地方欢迎指正。
WPF MVVM+EF增删改查 简单示例(二) 1对1 映射
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原文地址：http://www.cnblogs.com/qindongshou/p/5354955.html
