GridView\CheckBox

I am using VS 2008. I have a gridview with several columns that are
checkboxes. The data for each column is either a 1 or 0. When I try to
view the page in the browser I get an error "Specified cast is not
valid". Below is the code for the column. PL is the field name in the
datasource. It is a string field. I did change it to integer and still
received the same error message. What could be causing the error?
TIA

<asp:TemplateField>
<EditItemTemplate>
asp:CheckBox ID="CheckBox1" runat="server" Checked='<%#
Bind("PL") %>' />
</EditItemTemplate>
<ItemTemplate>
<asp:CheckBox ID="CheckBox1" runat="server" Checked='<%#
Bind("PL") %>'
Enabled="false" />
</ItemTemplate>

Jun 27 '08 #1

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1641

Mark Rae [MVP]

"gh" <gh@att.netwrote in message
news:eT*************@TK2MSFTNGP02.phx.gbl...

What could be causing the error?

The Checked tag of an <asp:CheckBox /webcontrol needs to be populated with
something that can be evaluated as a Boolean.

What happens if you modify your markup like so..?

Checked='<%# DataBinder.Eval(Container.DataItem, "PL") %>'
--
Mark Rae
ASP.NET MVP
http://www.markrae.net

Jun 27 '08 #2

Mark Rae [MVP] wrote:

"gh" <gh@att.netwrote in message
news:eT*************@TK2MSFTNGP02.phx.gbl...

>What could be causing the error?

The Checked tag of an <asp:CheckBox /webcontrol needs to be populated
with something that can be evaluated as a Boolean.

What happens if you modify your markup like so..?

Checked='<%# DataBinder.Eval(Container.DataItem, "PL") %>'

Mark:

I get the same error message (System.InvalidCastException: Specified
cast is not valid.
) on Line 26.

</EditItemTemplate>
Line 25: <ItemTemplate>
Line 26: <asp:CheckBox ID="CheckBox1"
runat="server" Checked='<%# DataBinder.Eval(Container.DataItem, "PL") %>'
Line 27: Enabled="false" />
Line 28: </ItemTemplate>

Thanks

Jun 27 '08 #3

Mark Rae [MVP]

"gh" <gh@att.netwrote in message
news:OY**************@TK2MSFTNGP05.phx.gbl...

>>What could be causing the error?

The Checked tag of an <asp:CheckBox /webcontrol needs to be populated
with something that can be evaluated as a Boolean.

What happens if you modify your markup like so..?

Checked='<%# DataBinder.Eval(Container.DataItem, "PL") %>'

Mark:

I get the same error message (System.InvalidCastException: Specified cast
is not valid.) on Line 26.

</EditItemTemplate>
Line 25: <ItemTemplate>
Line 26: <asp:CheckBox ID="CheckBox1"
runat="server" Checked='<%# DataBinder.Eval(Container.DataItem, "PL") %>'
Line 27: Enabled="false" />
Line 28: </ItemTemplate>

OK. What *precisely* is the value of "PL" out of the database, and what is
the datatype?

For this to work, it will need to be a datatype / value combination which
can be converted into a Boolean...
--
Mark Rae
ASP.NET MVP
http://www.markrae.net

Jun 27 '08 #4

Mark Rae [MVP] wrote:

"gh" <gh@att.netwrote in message
news:OY**************@TK2MSFTNGP05.phx.gbl...

>>>What could be causing the error?

The Checked tag of an <asp:CheckBox /webcontrol needs to be
populated with something that can be evaluated as a Boolean.

What happens if you modify your markup like so..?

Checked='<%# DataBinder.Eval(Container.DataItem, "PL") %>'

Mark:

I get the same error message (System.InvalidCastException: Specified
cast is not valid.) on Line 26.

</EditItemTemplate>
Line 25: <ItemTemplate>
Line 26: <asp:CheckBox ID="CheckBox1"
runat="server" Checked='<%# DataBinder.Eval(Container.DataItem, "PL") %>'
Line 27: Enabled="false" />
Line 28: </ItemTemplate>

OK. What *precisely* is the value of "PL" out of the database, and what
is the datatype?

For this to work, it will need to be a datatype / value combination
which can be converted into a Boolean...

It is a varchar. The value is 0 or 1. I tried a Convert.ToInt32, but
receeved an error about the bool value. I don' t control the table
structures and have to use what is given to me. Shouldn' t an integer 1
or 0 be evaluated as a bool?

Thanks

Jun 27 '08 #5

Mark Rae [MVP]

"gh" <gh@att.netwrote in message
news:Ox**************@TK2MSFTNGP02.phx.gbl...

>OK. What *precisely* is the value of "PL" out of the database, and what
is the datatype?

For this to work, it will need to be a datatype / value combination which
can be converted into a Boolean...

It is a varchar. The value is 0 or 1.

OK, well that's *never* going to work natively as you've already discovered.

I tried a Convert.ToInt32, but receeved an error about the bool value. I
don' t control the table structures and have to use what is given to me.

Hmm - OK... Where did you do the Convert.ToInt32?

Shouldn' t an integer 1 or 0 be evaluated as a bool?

Yes it should - which is why I'm wondering where you did the conversion...
--
Mark Rae
ASP.NET MVP
http://www.markrae.net

Jun 27 '08 #6

Mark Rae [MVP] wrote:

"gh" <gh@att.netwrote in message
news:Ox**************@TK2MSFTNGP02.phx.gbl...

>>OK. What *precisely* is the value of "PL" out of the database, and
what is the datatype?

For this to work, it will need to be a datatype / value combination
which can be converted into a Boolean...

It is a varchar. The value is 0 or 1.

OK, well that's *never* going to work natively as you've already
discovered.

>I tried a Convert.ToInt32, but receeved an error about the bool
value. I don' t control the table structures and have to use what is
given to me.

Hmm - OK... Where did you do the Convert.ToInt32?

>Shouldn' t an integer 1 or 0 be evaluated as a bool?

Yes it should - which is why I'm wondering where you did the conversion...

<asp:TemplateField>
<EditItemTemplate>
<asp:CheckBox ID="CheckBox1" runat="server"
Checked='<%# Convert.ToInt32(DataBinder.Eval(Container.DataItem , "PL"))
%>' />
</EditItemTemplate>
<ItemTemplate>
<asp:CheckBox ID="CheckBox1" runat="server"
Checked='<%# Convert.ToInt32(DataBinder.Eval(Container.DataItem , "PL"))
%>'
Enabled="false" />
</ItemTemplate>

Thanks

Jun 27 '08 #7

Mark Rae [MVP]

"gh" <gh@att.netwrote in message
news:eo**************@TK2MSFTNGP06.phx.gbl...

>Yes it should - which is why I'm wondering where you did the
conversion...

<asp:TemplateField>
<EditItemTemplate>
<asp:CheckBox ID="CheckBox1" runat="server"
Checked='<%# Convert.ToInt32(DataBinder.Eval(Container.DataItem , "PL"))
%>' />
</EditItemTemplate>
<ItemTemplate>
<asp:CheckBox ID="CheckBox1" runat="server"
Checked='<%# Convert.ToInt32(DataBinder.Eval(Container.DataItem , "PL"))
%>'
Enabled="false" />
</ItemTemplate>

OK, indulge me...

Change the above to the code below, and tell me what the Text shows next to
the CheckBoxes...

<asp:TemplateField>
<ItemTemplate>
<asp:CheckBox ID="CheckBox1" runat="server" Checked='<%#
DataBinder.Eval(Container.DataItem, "PL") %>' Enabled="false" />
</ItemTemplate>
</ asp:TemplateField>
--
Mark Rae
ASP.NET MVP
http://www.markrae.net

Jun 27 '08 #8

Mark Rae [MVP]

"Mark Rae [MVP]" <ma**@markNOSPAMrae.netwrote in message
news:%2****************@TK2MSFTNGP05.phx.gbl...

<asp:TemplateField>
<ItemTemplate>
<asp:CheckBox ID="CheckBox1" runat="server" Checked='<%#
DataBinder.Eval(Container.DataItem, "PL") %>' Enabled="false" />
</ItemTemplate>
</ asp:TemplateField>

Apologies - I meant this:

<asp:TemplateField>
<ItemTemplate>
<asp:CheckBox ID="CheckBox1" runat="server" Text='<%#
DataBinder.Eval(Container.DataItem, "PL") %>' />
</ItemTemplate>
</ asp:TemplateField>

--
Mark Rae
ASP.NET MVP
http://www.markrae.net

Jun 27 '08 #9

=?Utf-8?B?YnJ1Y2UgYmFya2Vy?=

as stated the "checked" value needs to be a bool. so:

Checked='<%# DataBinder.Eval(Container.DataItem, "PL").ToString() == "1" %>'

will work.

-- bruce (sqlwork.com)
"gh" wrote:

Mark Rae [MVP] wrote:
"gh" <gh@att.netwrote in message
news:OY**************@TK2MSFTNGP05.phx.gbl...

>>What could be causing the error?

The Checked tag of an <asp:CheckBox /webcontrol needs to be
populated with something that can be evaluated as a Boolean.

What happens if you modify your markup like so..?

Checked='<%# DataBinder.Eval(Container.DataItem, "PL") %>'
Mark:

I get the same error message (System.InvalidCastException: Specified
cast is not valid.) on Line 26.

</EditItemTemplate>
Line 25: <ItemTemplate>
Line 26: <asp:CheckBox ID="CheckBox1"
runat="server" Checked='<%# DataBinder.Eval(Container.DataItem, "PL") %>'
Line 27: Enabled="false" />
Line 28: </ItemTemplate>
OK. What *precisely* is the value of "PL" out of the database, and what
is the datatype?

For this to work, it will need to be a datatype / value combination
which can be converted into a Boolean...

It is a varchar. The value is 0 or 1. I tried a Convert.ToInt32, but
receeved an error about the bool value. I don' t control the table
structures and have to use what is given to me. Shouldn' t an integer 1
or 0 be evaluated as a bool?

Thanks

Jun 27 '08 #10

Mark Rae [MVP] wrote:

"Mark Rae [MVP]" <ma**@markNOSPAMrae.netwrote in message
news:%2****************@TK2MSFTNGP05.phx.gbl...

><asp:TemplateField>
<ItemTemplate>
<asp:CheckBox ID="CheckBox1" runat="server" Checked='<%#
DataBinder.Eval(Container.DataItem, "PL") %>' Enabled="false" />
</ItemTemplate>
</ asp:TemplateField>

Apologies - I meant this:

<asp:TemplateField>
<ItemTemplate>
<asp:CheckBox ID="CheckBox1" runat="server" Text='<%#
DataBinder.Eval(Container.DataItem, "PL") %>' />
</ItemTemplate>
</ asp:TemplateField>

Mark:

I have it working using the suggested markup:

Checked='<%# DataBinder.Eval(Container.DataItem, "PL").ToString() ==
"1" %>'.

Thanks

Jun 27 '08 #11