CheckBox inside gridView Bind Table

Question

User-909867351 posted

Hi

Please why this code does not work?

The ativo field is a boolean field on MYsql database

<asp:TemplateField HeaderText="ativo" SortExpression="ativo">
                                    <EditItemTemplate>
                                        <asp:HiddenField ID="hid_OldName" Value='<%# Eval("ativo") %>' runat="server" />
                                        <asp:CheckBox ID="CheckBox1" runat="server" Checked='<%# Eval("ativo") %>' />
                                    </EditItemTemplate>
                                    <ItemTemplate>                                        
                                        <asp:CheckBox ID="CheckBox1" runat="server" Checked='<%# Eval("ativo") %>'  Enabled="false" />
                                    </ItemTemplate>
                                </asp:TemplateField>

Got error somethins about conversion  not valid. The field is boolean ( tinyint(1)) 

Why is does not work?

Answer 1

User409696431 posted

What is the value when it throws the error?   Is the field nullable, and is it sometimes null?

Answer 2

User839733648 posted

Hi mariolopes,

According to your description and code, I suggest that you could modify the vlaue of CheckBox.

You may add Convert.ToBoolean() to the value you've got from database like below.

 <asp:CheckBox ID="CheckBox1" runat="server" Checked='<%# Convert.ToBoolean(Eval("ativo")) %>' Enabled="false" />

result:

Best Regards,

Jenifer

Answer 3

User-1716253493 posted

for null issue, you can modify select statement like below

SELECT ISNULL(activo,0) as activo

Answer 4

User-909867351 posted

Ok Janifer

Almost done. One problem when I edit the record the value stored is null and not the boolean value. Look at my code:

 <asp:TemplateField HeaderText="ativo" SortExpression="ativo">
                                    <EditItemTemplate>
                                        <asp:HiddenField ID="hid_OldName" Value='<%# Convert.ToBoolean(Eval("ativo")) %>' runat="server" />
                                        <asp:CheckBox ID="CheckBox1" runat="server" Checked='<%# Convert.ToBoolean(Eval("ativo")) %>' />
                                    </EditItemTemplate>
                                    <ItemTemplate>                                        
                                        <asp:CheckBox ID="CheckBox1" runat="server" Checked='<%# Convert.ToBoolean(Eval("ativo")) %>'  Enabled="false" />
                                    </ItemTemplate>
                                </asp:TemplateField>

and my sql datasource

   <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:ConnectionString %>" ProviderName="<%$ ConnectionStrings:ConnectionString.ProviderName %>" SelectCommand="select * from alunos where ativo=1 order by nome" UpdateCommand="update alunos set ativo=?,nome=?,telemovel=?,email=?,nome_pai=?,telemovel_pai=? where id=?">
                            <UpdateParameters>
                                <asp:Parameter Name="ativo" Type="Boolean" />
                                <asp:Parameter Name="nome" Type="String" />
                                <asp:Parameter Name="telemovel" Type="String" />
                                <asp:Parameter Name="email" Type="String" />
                                <asp:Parameter Name="nome_pai" Type="String" />
                                <asp:Parameter Name="telemovel_pai" Type="String" />
                                <asp:Parameter Name="id" Type="Int16" />
                            </UpdateParameters>
                        </asp:SqlDataSource>

It stores null value and not the expected value.

Thank you

Answer 5

User-1716253493 posted

<asp:CheckBox ID="CheckBox1" runat="server" Checked='<%# Bind("ativo") %>' />

Eval is one way binding, it's read db value but not pass when update/insert

Use Bind() instead to save it

To avoid null binding error, convert it to 0 in select query, or update all nulls to zeros

Answer 6

User-909867351 posted

If I use Bind I got error something like the conversion is not valid.

All the values have 0 or 1 value for column ativo. None of them have Null values, I don't understand what's happened.

Detalhes da Exceção: System.InvalidCastException: A conversão especificada não é válida

Erro de origem: 

Linha 89: </EditItemTemplate> Linha 90: <ItemTemplate> Linha 91: <asp:CheckBox ID="CheckBox1" runat="server" Checked='<%# Bind("ativo") %>' Enabled="False" /> Linha 92: </ItemTemplate> Linha 93: </asp:TemplateField>

Answer 7

User475983607 posted
As suggested many times above, convert the result to a Boolean and write code to handle null if you allow nulls.

Answer 8

User-909867351 posted

Sorry Guys,

Found the issue you are absolutey right.