To display a picture from a database to a picture box when selected in a combobox, and to insert, upload, and update pictures to a database using VB.NET and ODBC/ODBCCommand, you can follow these steps:
1. Set up your project:
- Create a new VB.NET project.
- Add a combobox, a picture box, and a button to your form.
- Import the necessary namespaces:
Code:
vb
Imports System.Data.Odbc
Imports System.IO
2. Establish a database connection:
- Create a connection string to connect to your PHPMyAdmin database:
Code:
vb
Dim connectionString As String = "Driver={MySQL ODBC 8.0 Unicode Driver};Server=<server_name>;Database=<database_name>;Uid=<username>;Pwd=<password>;"
- Create an
OdbcConnection
object to establish a connection:
Code:
vb
Dim connection As New OdbcConnection(connectionString)
3. Populate the combobox with data from the database:
- In the form load event, fetch the data from the database and populate the combobox:
Code:
vb
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim command As New OdbcCommand("SELECT picture_name FROM your_table", connection)
connection.Open()
Dim reader As OdbcDataReader = command.ExecuteReader()
While reader.Read()
ComboBox1.Items.Add(reader("picture_name").ToString())
End While
reader.Close()
connection.Close()
End Sub
4. Display the selected picture in the picture box:
- Handle the combobox selected index changed event:
Code:
vb
Private Sub ComboBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ComboBox1.SelectedIndexChanged
If ComboBox1.SelectedIndex <> -1 Then
Dim selectedPictureName As String = ComboBox1.SelectedItem.ToString()
Dim command As New OdbcCommand("SELECT picture_data FROM your_table WHERE picture_name = ?", connection)
command.Parameters.AddWithValue("pictureName", selectedPictureName)
connection.Open()
Dim pictureData As Byte() = DirectCast(command.ExecuteScalar(), Byte())
connection.Close()
If pictureData IsNot Nothing Then
Dim ms As New MemoryStream(pictureData)
PictureBox1.Image = Image.FromStream(ms)
End If
End If
End Sub
5. Insert or update picture data to the database:
- Handle the button click event to insert or update the picture:
Code:
vb
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
If ComboBox1.SelectedIndex <> -1 Then
Dim selectedPictureName As String = ComboBox1.SelectedItem.ToString()
Dim ms As New MemoryStream()
PictureBox1.Image.Save(ms, PictureBox1.Image.RawFormat)
Dim pictureData As Byte() = ms.ToArray()
Dim command As New OdbcCommand("UPDATE your_table SET picture_data = ? WHERE picture_name = ?", connection)
command.Parameters.AddWithValue("pictureData", pictureData)
command.Parameters.AddWithValue("pictureName", selectedPictureName)
connection.Open()
command.ExecuteNonQuery()
connection.Close()
End If
End Sub
6. Insert a new picture to the database:
- Handle the button click event to insert a new picture:
Code:
vb
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
If OpenFileDialog1.ShowDialog() = DialogResult.OK Then
Dim fileName As String = Path.GetFileName(OpenFileDialog1.FileName)
Dim fileStream As New FileStream(OpenFileDialog1.FileName, FileMode.Open, FileAccess.Read)
Dim fileData As Byte() = New Byte(fileStream.Length - 1) {}
fileStream.Read(fileData, 0, CInt(fileStream.Length))
fileStream.Close()
Dim command As New OdbcCommand("INSERT INTO your_table (picture_name, picture_data) VALUES (?, ?)", connection)
command.Parameters.AddWithValue("pictureName", fileName)
command.Parameters.AddWithValue("pictureData", fileData)
connection.Open()
command.ExecuteNonQuery()
connection.Close()
ComboBox1.Items.Add(fileName)
End If
End Sub
Remember to replace
<server_name>
,
<database_name>
,
<username>
, and
<password>
with your actual database connection details. Also, adjust the table and column names accordingly.
These steps should allow you to display, insert, update, and upload pictures to a database using VB.NET and ODBC/ODBCCommand.