How to get null value from database for checkbox in gridview

Question

I have a checkbox in gridview.

<asp:CheckBox ID="chkStatus" runat="server" Checked='<%#GetStatus(Eval("VaccinationCompletedStatus")) %>'/> 

The GetStatus function is as follows

  Public Function GetStatus(ByVal objStatus As Object) As Boolean If objStatus = True Then Return True ElseIf objStatus = False Then Return False Else Return False End If End Function 

But if Status comes as null from the database, then one error appears, since System.DBNull cannot be passed to the object. If null comes from the database, I want to set the false flag.

Answer 1

You can check DBNull first:

 If DBNull.Value.Equals(objStatus) Then Return False Else Return objStatus End If 

Answer 2

Use the TypeOf function to check if the input type is logical. If it is not just returning false.

 If TypeOf objStatus Is Boolean Then Your code here Else Return False End If 

Answer 3

 <asp:TemplateField HeaderText="foo" > <ItemTemplate> <asp:CheckBox runat="server" Checked='<%# Eval("foo").GetHashCode() == 1 %>' Enabled="false" Visible='<%# Eval("foo").GetType() == typeof(Boolean) %>' /> </ItemTemplate> </asp:TemplateField>