I have written the code below to read data from an Excel sheet and display data in a combobox in Visual Basic.
However, when I click "run" nothing is displayed.
Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim MyConnection As New OleDb.OleDbConnection
Dim MyCommand As New OleDb.OleDbCommand
Dim filePath, sql As String
filePath = "C:\Users\Nour\Desktop\projects\grade10\grade10\atlas.xlsx"
sql = "Select continent from [Sheet1]"
MyConnection.ConnectionString = $"Provider= Microsoft.Jet._OLEDB 11.0;data source = {filePath};Extended_Properties=Excel 8.0"
MyConnection.Open()
MyCommand.Connection = MyConnection
MyCommand.CommandText = sql
Dim da As New OleDb.OleDbDataAdapter
da.SelectCommand = MyCommand
Dim dt As New DataTable
da.Fill(dt)
Me.ComboBox1.DataSource = dt
Me.ComboBox1.DisplayMember = dt.Columns(0).ToString
MyConnection.Close()
Try this code
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
Dim fname As String = "C:\Users\Nour\Desktop\projects\grade10\grade10\atlas.xlsx"
Dim connectionStringTemplate As String = "Provider=Microsoft.ACE.OLEDB.12.0;" + "Data Source={0};" + "Extended Properties=""Excel 12.0;HDR=Yes"""
Dim connectionString As String = String.Format(connectionStringTemplate, fname)
Dim sqlSelect As String = "SELECT * FROM [Sheet1$];"
Dim workbook As DataSet = New DataSet()
Dim excelAdapter As System.Data.Common.DataAdapter = New System.Data.OleDb.OleDbDataAdapter(sqlSelect, connectionString)
excelAdapter.Fill(workbook)
Dim worksheet As DataTable = workbook.Tables(0)
ComboBox1.DataSource = worksheet
Me.ComboBox1.DisplayMember = worksheet.Columns(0).ToString
End Sub
To read an xlsx file, rather than an xls file, you will need the ACE provider instead of the JET provider. You need to add the Extended Property "HDR=Yes" to tell it there is a header row.
The name of a worksheet needs a $
after it.
To make up a connection string, you can use a connectionstringbuilder - it will take care of adding any quotes or whatever is needed to create a valid connection string from the individual parts.
A DataAdapter will open and close the connection for you.
Some entities use unmanaged resources (ie they don't get automatically cleaned up after use) - they will have a .Dispose()
method which will release those resources. Or you can use the Using
construct to have it taken care of for you.
I used the ColumnName
property instead of ToString
as it is more obvious what it is.
I made a small Excel xlsx file to test with and used this program:
Imports System.Data.OleDb
Public Class Form1
Sub PopulateCB()
Dim filepath = "C:\temp\Continents.xlsx"
Dim csb As New OleDbConnectionStringBuilder
csb.Provider = "Microsoft.ACE.OLEDB.12.0"
csb.DataSource = filepath
csb.Add("Extended Properties", "Excel 12.0 Xml;HDR=YES")
Dim sql = "SELECT Continent FROM [Sheet1$]"
Dim dt As New DataTable
Using da As New OleDbDataAdapter(sql, csb.ConnectionString)
da.Fill(dt)
End Using
ComboBox1.DataSource = dt
ComboBox1.DisplayMember = dt.Columns(0).ColumnName
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
PopulateCB()
End Sub
End Class
to get a combobox like this:
First thing to check before going into code, compatibility between your database and your excel . If you are using a 32bits excel version you will never be able to query a 64bits database.
Start with something simple, and then work up to more complex things.
Imports Excel = Microsoft.Office.Interop.Excel
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles Button1.Click
Dim xlApp As Excel.Application
Dim xlWorkBook As Excel.Workbook
Dim xlWorkSheet As Excel.Worksheet
xlApp = New Excel.ApplicationClass
xlWorkBook = xlApp.Workbooks.Open("c:\test1.xlsx")
xlWorkSheet = xlWorkBook.Worksheets("sheet1")
'display the cells value B2
MsgBox(xlWorkSheet.Cells(2, 2).value)
'edit the cell with new value
xlWorkSheet.Cells(2, 2) = "http://vb.net-informations.com"
xlWorkBook.Close()
xlApp.Quit()
releaseObject(xlApp)
releaseObject(xlWorkBook)
releaseObject(xlWorkSheet)
End Sub
Private Sub releaseObject(ByVal obj As Object)
Try
System.Runtime.InteropServices.Marshal.ReleaseComObject(obj)
obj = Nothing
Catch ex As Exception
obj = Nothing
Finally
GC.Collect()
End Try
End Sub
End Class
Make this work, and then add in a ComboBox object.
http://vb.net-informations.com/excel-2007/vb.net_excel_2007_open_file.htm
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