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Read Excel Cell in VB

    Question

  • I am trying to read in the value (string or int) of a single cell from an excel spreadsheet.

    I have created a spreadsheet c:\temp.xls with the string "asdf" in cell A1. I am trying to read it in VB express using the following:

    Dim cn As System.Data.OleDb.OleDbConnection
    Dim cmd As System.Data.OleDb.OleDbDataAdapter
    Dim ds As New System.Data.DataSet()

    cn = New System.Data.OleDb.OleDbConnection("provider=Microsoft.Jet.OLEDB.4.0;" & _
    "data source=C:\temp.xls;Extended Properties=Excel 8.0;")

    cmd = New System.Data.OleDb.OleDbDataAdapter("select * from [Sheet1$A1:A1]", cn)

    cn.Open()
    cmd.Fill(ds)
    cn.Close()

    MsgBox(CType(ds.Tables(0).Rows(0).Item(0), Object).ToString)


    This throws an exception saying there is no row 0. If I delete the A1:A1 range, I then just get an empty string.

    Any help is appreciated, please keep it in VB express.
    Tuesday, July 03, 2007 6:08 PM

Answers

  • Hi reefaddict,

       I agree with Derek Smyth, for reading the header data, you have to modify your conncetion string like the following:

    Code Snippet
    Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\MyExcel.xls;Extended Properties="Excel 8.0;HDR=No;IMEX=1";

       "HDR=Yes;" indicates that the first row contains columnnames, not data. "HDR=No;" indicates the opposite.

       Hope this can help you!

    Thanks!

    Thursday, July 05, 2007 7:45 AM
  • You can use the ADO.NET to query the excel sheet without having excel loaded.

     

    To use the Excel object model, requires the appropriate version of Excel to be installed on the machine.   This is Office Automation and you are simply automating what is installed.   Using a product with just the reference added will probably not work as this dll has dependencies on other DLL's which are there when you install the product.   The references are simply interop assemblies allowing your code to interact with the Excel DLL's.

     

     

    Thursday, July 05, 2007 10:49 PM
  • Hi js06,

     

    The choice of using one method over the other really depends on how the data is stored in Excel. There is generally two ways to store data in Excel, one is where a sheet contains row after row of data and the other is where data is scattered about the place usually with sub totals. Scattered is the wrong word but generally the data isn't one row after the other and might be lists with totals.

     

    Accessing Excel using ADO.NET and a connection string really only works when the data is held row by row, very much like a database table. You can really only select a 'square' range of data as a chunk. If you have data in that format then use ADO.NET it is incredibly fast and uses much less resources.

     

    If your data is in a format where the values are 'scattered' not in as a table but maybe a value in cell A13, B13, C67, and so on then using ADO.NET isn't a very good option and you really need to add a reference and work with Excel using OLE Automation (the technical name for the approach your example takes). Using this approach means you can pick values from individual cells.

     

    Another difference comes with changing the style of the sheet, you cannot change the colour of a cell using ADO.NET but you can with OLE Automation, you can't specify a formula in ADO.NET (I don't think).

     

    It all depends on the format or layout of the data and the task you want to perform on the spreadsheet. If all your interested in is data and that data is in one square chuck use ADO.NET, otherwise reference Excel.

     

     

    Thursday, July 05, 2007 11:06 PM

All replies

  • Do a search for excel automation here in the forum
    Tuesday, July 03, 2007 6:58 PM
  • Everything I have found uses Excel.Application, which I can't use because I only have VB Express.

    I have already spent quite some time searching for this. Could someone please tell me what is wrong with what I have?
    Tuesday, July 03, 2007 7:08 PM
  • Alright,

     

    Yip you need have a header row..... so for example if I have your string asdf in cell A1 then I also get your error. But if I add a header row, cell A1 = "Col1" and A2 = "asdf", then everything works. If you think about it that should be the expected behaviour. The excel sheet acts like a database table, which have column names.

     

    The error says there is no row 0, that error is because your trying to access row 0 in your data table but there is no row 0 as the asdf is used as the column header. If you look at your table in the debugger you'll see one column in your table called asdf. Add in a header row in A1 and start your data entry at row A2 and your code will work.

     

     

    Tuesday, July 03, 2007 7:11 PM
  • I thought i would give this to you.

    You can use excel.application in vbexpress.

     

    This may be better if you want to use an existing excel file without having to modify it with headers

    use it if you like or disregard

     

    Dim oExcel As Excel.Application

    Dim oBook As Excel.Workbook

    Dim oSheet As Excel.Worksheet

    oExcel = CreateObject("Excel.Application")

    oBook = oExcel.Workbooks.Open("c:\Book1.xls", [ReadOnly]:=False)

    oExcel.Visible = False

    oExcel.DisplayAlerts = False 'So It doesnt prompt

    oSheet = oBook.Worksheets("Sheet1")

    oSheet.Select()

     

    Dim a1string As String

    a1string = oSheet.Range("A1").Value

    oExcel.Quit()

    MsgBox(a1string)

    Tuesday, July 03, 2007 8:30 PM
  • Depending on what you want to do with the excel files you might be interested in a program called spreadsheet gear

    It allows you to use an embedded view to open and work with excel files without having to have excel installed.  Your end users do not need excel either and it's royalty free.

     

    I agree that excel itself is much more powerful but SG is catching up.  If i had a choice i would rather use excel but this can do what excel can't in certain areas.

     

    And there is a free version from microsoft in your registration benefits portal.

    Thought you might be interested.

    Wednesday, July 04, 2007 1:14 AM
  • Hi reefaddict,

       I agree with Derek Smyth, for reading the header data, you have to modify your conncetion string like the following:

    Code Snippet
    Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\MyExcel.xls;Extended Properties="Excel 8.0;HDR=No;IMEX=1";

       "HDR=Yes;" indicates that the first row contains columnnames, not data. "HDR=No;" indicates the opposite.

       Hope this can help you!

    Thanks!

    Thursday, July 05, 2007 7:45 AM
  • Feng or Derek,

     

    Can you tell me what would be better to use, a connection or work with excel like my example?

    Are there advantages for one over the other?

     

    If you have a computer that does not have excel installed, can you still access the files with either or both methods?

    Can you add the reference to excel in vb if the developing computer does not have excel installed?

     

    I haven't tried any of these examples on a computer that does not have excel installed yet.

     

    Thanks

    Thursday, July 05, 2007 9:54 PM
  • You can use the ADO.NET to query the excel sheet without having excel loaded.

     

    To use the Excel object model, requires the appropriate version of Excel to be installed on the machine.   This is Office Automation and you are simply automating what is installed.   Using a product with just the reference added will probably not work as this dll has dependencies on other DLL's which are there when you install the product.   The references are simply interop assemblies allowing your code to interact with the Excel DLL's.

     

     

    Thursday, July 05, 2007 10:49 PM
  • Hi js06,

     

    The choice of using one method over the other really depends on how the data is stored in Excel. There is generally two ways to store data in Excel, one is where a sheet contains row after row of data and the other is where data is scattered about the place usually with sub totals. Scattered is the wrong word but generally the data isn't one row after the other and might be lists with totals.

     

    Accessing Excel using ADO.NET and a connection string really only works when the data is held row by row, very much like a database table. You can really only select a 'square' range of data as a chunk. If you have data in that format then use ADO.NET it is incredibly fast and uses much less resources.

     

    If your data is in a format where the values are 'scattered' not in as a table but maybe a value in cell A13, B13, C67, and so on then using ADO.NET isn't a very good option and you really need to add a reference and work with Excel using OLE Automation (the technical name for the approach your example takes). Using this approach means you can pick values from individual cells.

     

    Another difference comes with changing the style of the sheet, you cannot change the colour of a cell using ADO.NET but you can with OLE Automation, you can't specify a formula in ADO.NET (I don't think).

     

    It all depends on the format or layout of the data and the task you want to perform on the spreadsheet. If all your interested in is data and that data is in one square chuck use ADO.NET, otherwise reference Excel.

     

     

    Thursday, July 05, 2007 11:06 PM
  • Thank you spotty and derek, it makes more sense now.
    Friday, July 06, 2007 2:11 AM
  •  reefaddict wrote:
    I am trying to read in the value (string or int) of a single cell from an excel spreadsheet.

    I have created a spreadsheet c:\temp.xls with the string "asdf" in cell A1. I am trying to read it in VB express using the following:

    Dim cn As System.Data.OleDb.OleDbConnection
    Dim cmd As System.Data.OleDb.OleDbDataAdapter
    Dim ds As New System.Data.DataSet()

    cn = New System.Data.OleDb.OleDbConnection("provider=Microsoft.Jet.OLEDB.4.0;" & _
    "data source=C:\temp.xls;Extended Properties=Excel 8.0;")

    cmd = New System.Data.OleDb.OleDbDataAdapter("select * from [Sheet1$A1:A1]", cn)

    cn.Open()
    cmd.Fill(ds)
    cn.Close()

    MsgBox(CType(ds.Tables(0).Rows(0).Item(0), Object).ToString)


    This throws an exception saying there is no row 0. If I delete the A1:A1 range, I then just get an empty string.

    Any help is appreciated, please keep it in VB express.
    Wednesday, August 22, 2007 4:14 PM
  • The problem is that you are trying to get A1 to populate the dataset  -  Use [Sheet1$] without A1:A1

     

    This works

     

    Dim opendlg As New OpenFileDialog

    opendlg.Filter = "Excel Files (*.xls)|*.xls|All Files (*.*)|*.*"

    If opendlg.ShowDialog() = Windows.Forms.DialogResult.OK Then

    Dim pathname As String = opendlg.FileName

    'MsgBox(pathname)

    Dim connect As System.Data.OleDb.OleDbConnection = New System.Data.OleDb.OleDbConnection("provider=Microsoft.Jet.OLEDB.4.0;" & _

    "data source=" & pathname & ";Extended Properties=Excel 8.0;")

     

    'you can eliminate the openfiledialog and just put C:\temp.xls where pathname is on the above line if you want

     

     Dim adapter As System.Data.OleDb.OleDbDataAdapter = New System.Data.OleDb.OleDbDataAdapter("select * from [Sheet1$]", connect)

    connect.Open()

     

    'This is to fill the datagridview table

    'adapter.Fill(Me.Database1DataSet.Table1)

     

    'This is just to get the data shown in the messagebox

    Dim ds As New System.Data.DataSet()

    adapter.Fill(ds)

    MsgBox(CType(ds.Tables(0).Rows(0).Item(0), Object).ToString)

    'End messagebox data get

    connect.Close()

    Wednesday, August 22, 2007 5:58 PM