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Casting DBNull in Raddatepicker in Grid
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This is a migrated thread and some comments may be shown as answers.
Hafizul Fadhli
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Hafizul Fadhli asked on 16 Aug 2018, 02:08 AM

<telerik:GridTemplateColumn HeaderText="Tarikh Luput" HeaderStyle-HorizontalAlign="Center" UniqueName="ExpDate">
                                        <HeaderStyle Width="100px" />
                                        <ItemTemplate>
                                            <telerik:RadDatePicker ID="dtExp" runat="server" AutoPostBack="true" OnSelectedDateChanged="dtExp_TextChanged"
                                                DBSelectedDate='<%# IIf(IsDBNull(Eval("EXPIRY_DATE")), Nothing, Convert.ToDateTime(Eval("EXPIRY_DATE")))%>'>
                                                <DateInput
                                                        DateFormat="MM/dd/yyyy"
                                                        DisplayDateFormat="dd/MM/yyyy"
                                                        runat="server" >
                                                </DateInput>
                                            </telerik:RadDatePicker>
                                        </ItemTemplate>
                                    </telerik:GridTemplateColumn>  

 

It returns "Object cannot be cast from DBNull to other types." error. Help?

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Tsvetomir
Telerik team
answered on 20 Aug 2018, 03:53 PM
Hi Hafizul,

The RadGrid control is capable of handling null values by default, so it is not needed to use a conditional data binding and explicit converting. You can use the following: 

DbSelectedDate='<%# Eval("EXPIRY_DATE") %>'

Additionally, when using VB.NET it is recommended to use IF instead of IIF, since the IIF function is executed for each part of the statement. You can find more information in the IF vs IIF MSDN forum post. Moreover, Nothing is used to specify that the variable's reference is not pointing to anything, while DBNull.Value is an object used to point out that the value coming from the DataBase is null.

If you want to keep using the conditional binding approach, the DBSelectedDate property should look like this:
 
DBSelectedDate='<%# If(IsDBNull(Eval("OrderDate")), DBNull.Value, Eval("OrderDate"))%>'

In general, we recommend that you take advantage of the built-in features of controls, so in this case you can skip the condition for the DBSelectedValue.

Kind regards,
Tsvetomir
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Hafizul Fadhli
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Tsvetomir
Telerik team
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