ObjectDataSource.Select() not always firing on page postback

问题

I have a form with:

1 text box ("MyTextBox")
3 check boxes ("MyCheckBox1", "MyCheckBox2", "MyCheckBox3")
1 submit button ("MySubmitButton")
1 ObjectDataSource ("MyObjectDataSource")
1 GridView ("MyGridView")

My ObjectDataSource looks like this:

<asp:ObjectDataSource ID="MyObjectDataSource" runat="server"
                          SelectMethod="MySelectMethod"
                          TypeName="MyTypeName">
    <SelectParameters>
        <asp:ControlParameter Name="MyRegularString"
                              Type="String"
                              ControlID="MyTextBox"
                              PropertyName="Text" />

        <asp:Parameter Name="MySpecialString"
                       Type="String" />
    </SelectParameters>
</asp:ObjectDataSource>

The second parameter ("MySpecialString") is filled like this:

Protected Sub MyObjectDataSource_Selecting(...) Handles MyObjectDataSource.Selecting

   Dim MySpecialString As String = "Key1=" & MyCheckBox1.Checked.ToString & ";" & _
                                   "Key2=" & MyCheckBox2.Checked.ToString & ";" & _
                                   "Key3=" & MyCheckBox3.Checked.ToString & ";"

   e.InputParameters.Item("MySpecialString") = MySpecialString

End Sub

Whenever I change the value of MyTextBox and press MySubmitButton, the select method of MyObjectDataSource is invoked and everything works OK.

But if I change the value of any of my check boxes (without changing the value of MyTextBox) and press MySubmitButton, the select method is not invoked, thus the "MyObjectDataSource_Selecting" event doesn't take place and I get the same results as before.

One way I found to work around this was to explicitly invoke MyGridView.DataBind method whenever MySubmitButton was clicked. Is this the best way to handle these type of parameters? What I am afraid is that this may cause the select method to be called twice making the page slower.

Thanks in advance for any help.

回答1:

This is what I ended up doing.

Replaced all the asp:ControlParameters with asp:Parameters.
Explicitly invoked MyGridView.DataBind method whenever MySubmitButton was clicked.

I checked and the select method is not invoked twice when doing this.

来源：https://stackoverflow.com/questions/10593015/objectdatasource-select-not-always-firing-on-page-postback

标签

ASP.NET

vb.net

objectdatasource