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POQuirky SELECT from Excel file via OleDbDataAdapter method (C#)
 

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  1. POQuirky SELECT from Excel file via OleDbDataAdapter method (C#)
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    <p>I have got an Excel file in this form :</p> <pre><code>Column 1 Column 2 Column 3 data1 data2 data1 data2 data1 data2 data1 data2 data1 data2 data3 </code></pre> <p>That is, the whole Column 3 is empty except for the last row. I am accessing the Excel file via OleDbDataAdapter, returning a DataTable: here's the code. </p> <pre><code>query = "SELECT * FROM [" + query + "]"; objDT = new DataTable(); objCmdSQL = this.GetCommand(); objCmdSQL.CommandText = query; objSQLDad = new OleDbDataAdapter(objCmdSQL); objSQLDad.Fill(objDT); return objDT; </code></pre> <p>The point is, in this scenario my code returns a DataTable with just Column 1 and Column 2.<br> My guess is that JET engine tries to infer column type by the type of the very first cell in every column; being the first value null, the whole column is ignored.<br> I tried to fill in zeros and this code is actually returning all three columns; this is obviously the least preferable solution because I have to process large numbers of small files.<br> Inverting the selection range (from, i.e. "A1:C5" to "C5:A1" ) doesn't work either. I'm looking for something more elegant.<br> I have already found a couple of posts discussing type mismatch (varchar cells in int columns and vice versa) but actually haven't found anything related to this one.<br> Thanks for reading!</p> <p><em>edit</em> </p> <p>Weird behavior again. I have to work on mostly Excel 2003 .xls files, but since this question has been answered I thought I could test my code against Excel 2007 .xslx files. The connection string is the following:</p> <pre><code>string strConn = @"Provider=Microsoft.ACE.OLEDB.12.0; Data Source=" + _fileName.Trim() + @";Extended Properties=""Excel 12.0;HDR=No;IMEX=1;"""; </code></pre> <p>I get the "External table is not in the expected format" exception which I reckon is the standard exception when there is a version mismatch between ACE/JET and the file being opened.</p> <p>The string </p> <pre><code>Provider=Microsoft.ACE.OLEDB.12.0 </code></pre> <p>means that I am using the most recent version of OLEDB, I took a quick peek around and this version is used everywhere there is need of connecting to .xlsx files.<br> I have tried with just a vanilla provider ( just Excel 12.0, without IMEX nor HDR ) but I get the same exception.<br> I am on .NET 2.0.50727 SP2, maybe time to upgrade?</p>
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    1. This table or related slice is empty.
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    1. COSo there are no Headers on the columns in Excel? And have you tried the IMEX switch on the connection?
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    2. COThere are headers, but I am selecting on the portion of the table that just contains the data avoiding horizontal and vertical headers.
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