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POASP.net VB Gridview Update cast values
 

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    <p>I have a GridView with datasource from the MS Access database. It is </p> <blockquote> <p>SELECT * FROM [TODO] ORDER BY [Name]</p> </blockquote> <p>The UPDATE query is</p> <blockquote> <p>UPDATE [TODO] SET [Staff] = CInt(@Staff), [Title] = @Title, [Deadline] = @Deadline, [Status] = CInt(@Status) WHERE [todoID] = @ID</p> </blockquote> <p>Two of the returned values are foreign keys (integer) for another tables - Status and Staff So I replaced two EditItemTemplates with DropDownLists, assigning them other DataSources and binding the selected index to the foreign key.</p> <p>This results in GridView generating this HTML:</p> <pre><code>&lt;select name="ctl00$ContentPlaceHolder1$GridView1$ctl02$DropDownList1" id="ContentPlaceHolder1_GridView1_DropDownList1_0"&gt; &lt;option value="1"&gt;John Doe&lt;/option&gt; &lt;option value="2"&gt;William Jenkins&lt;/option&gt; &lt;option value="3"&gt;Kate Piper&lt;/option&gt; &lt;option selected="selected" value="4"&gt;Alison Fisher&lt;/option&gt; &lt;/select&gt; </code></pre> <p>And this results in the following ASP.NET error when updating the record</p> <blockquote> <p>Exception Details: System.Data.OleDb.OleDbException: Invalid use of Null</p> </blockquote> <p>I also tried not to cast values in the query - still no success, but another error is thrown:</p> <blockquote> <p>Conversion from type 'DBNull' to type 'Integer' is not valid.</p> </blockquote> <p>I am really new in ASP.NET, all my experience is based on other languages. I will really appreciate any help</p>
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    1. USVladimir Hraban
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