从数据库向每个usercontrol的图片框显示图片？

用户控制代码：

private string lastName; public string LastName { get { return lastName; } set { lastName = value; textBox1.Text = value; } } 

表格代码：

  using (SqlConnection myDatabaseConnection = new SqlConnection(myConnectionString.ConnectionString)) { myDatabaseConnection.Open(); using (SqlCommand SqlCommand = new SqlCommand("Select LastName, Image from Employee", myDatabaseConnection)) { int i = 0; SqlDataReader DR1 = SqlCommand.ExecuteReader(); while (DR1.Read()) { i++; UserControl2 usercontrol = new UserControl2(); usercontrol.Tag = i; usercontrol.LastName = (string)DR1["LastName"]; flowLayoutPanel1.Controls.Add(usercontrol); } } } 

使用上面的代码，我可以在每个usercontrol的文本框中显示数据库中的每个LastName。 如何将数据库中的图片显示给每个usercontrol的图片框？

这是我从数据库中显示单个图像的方式：

  using (SqlConnection myDatabaseConnection = new SqlConnection(myConnectionString.ConnectionString)) { myDatabaseConnection.Open(); using (SqlCommand SqlCommand = new SqlCommand("Select LastName, Image from Employee where ID = @a", myDatabaseConnection)) { SqlCommand.Parameters.AddWithValue("@a", textBox1.Text); DataSet DS = new DataSet(); SqlDataAdapter da = new SqlDataAdapter(SqlCommand); da.Fill(DS, "Images"); var imagesTable = DS.Tables["Images"]; var imagesRows = imagesTable.Rows; var count = imagesRows.Count; if (count <= 0) return; var imageColumnValue = imagesRows[count - 1]["Image"]; if (imageColumnValue == DBNull.Value) return; var data = (Byte[])imageColumnValue; using (var stream = new MemoryStream(data)) { pictureBox1.Image = Image.FromStream(stream); } } } 

Answer 1

要一次访问多个控件（在您的情况下为PictureBoxes），请使用foreach循环。

 foreach (Control control in this.Controls) { if (control is PictureBox) { PictureBox pic = (PictureBox)control; pic.Image = Image.FromStream(stream); //something similar, this will only load the same image to every PictureBox } } 

Answer 2

使UserControl构造函数重载以接收姓氏和图像字节。 然后你可以在循环中执行此操作：

  while (DR1.Read()) { i++; UserControl2 usercontrol = new UserControl2((string)DR1["LastName"], (Byte[])DR1["Image"]); usercontrol.Tag = i; flowLayoutPanel1.Controls.Add(usercontrol); } 

这是更新的UserControl（使用其他问题的InvokeOnClick（）代码）。 请注意新构造函数中我们如何从字节创建图像并将其分配给PictureBox：

 public partial class UserControl2 : UserControl { private string lastName; public string LastName { get { return lastName; } set { lastName = value; textBox1.Text = value; } } public UserControl2(string LastName, byte[] data) { InitializeComponent(); WireAllControls(this); this.LastName = LastName; try { using (var stream = new System.IO.MemoryStream(data)) { pictureBox1.Image = Image.FromStream(stream); } } catch (Exception) { MessageBox.Show("Error Loading Image for " + LastName); } } public UserControl2() { InitializeComponent(); WireAllControls(this); } private void WireAllControls(Control cont) { foreach (Control ctl in cont.Controls) { ctl.Click += ctl_Click; if (ctl.HasChildren) { WireAllControls(ctl); } } } private void ctl_Click(object sender, EventArgs e) { this.InvokeOnClick(this, EventArgs.Empty); } } 

Answer 3

用户控制代码：

  public void showpictures() { { using (SqlConnection myDatabaseConnection = new SqlConnection(myConnectionString.ConnectionString)) { myDatabaseConnection.Open(); using (SqlCommand SqlCommand = new SqlCommand("Select LastName, Image from Employee where LastName = @a", myDatabaseConnection)) { SqlCommand.Parameters.AddWithValue("@a", textBox1.Text); DataSet DS = new DataSet(); SqlDataAdapter da = new SqlDataAdapter(SqlCommand); da.Fill(DS, "Images"); var imagesTable = DS.Tables["Images"]; var imagesRows = imagesTable.Rows; var count = imagesRows.Count; if (count <= 0) return; var imageColumnValue = imagesRows[count - 1]["Image"]; if (imageColumnValue == DBNull.Value) return; var data = (Byte[])imageColumnValue; using (var stream = new MemoryStream(data)) { pictureBox1.Image = Image.FromStream(stream); } } } } } 

形成

  while (DR1.Read()) { i++; UserControl2 usercontrol = new UserControl2(); usercontrol.Tag = i; usercontrol.LastName = (string)DR1["LastName"]; usercontrol.showpictures(); flowLayoutPanel1.Controls.Add(usercontrol); }