Please help: "Specified cast is not valid" error when binding the Visible propery of a hyperlink control

[keithb]

Using a GridView, I get a "Specified cast is not valid" error when binding
the Visible propery of a hyperlink control to a DataTable text field. The
error goes away if I replace the data binding statement with "true" or
"false". This code causes the error:

<asp:HyperLin k ID="HyperLink1 "
runat="server"
NavigateUrl='<% #
Eval("c2Hyperli nk1Link") %>'
Target="_blank"
Text='<%#
Eval("c2Hyperli nk1Text") %>'
Visible='<%#
Eval("c2Hyperli nk1Visible") %>' ></asp:HyperLink>

This code runs without error:

<asp:HyperLin k ID="HyperLink1 "
runat="server"
NavigateUrl='<% #
Eval("c2Hyperli nk1Link") %>'
Target="_blank"
Text='<%#
Eval("c2Hyperli nk1Text") %>'
Visible="true" >'

></asp:HyperLink>

I do not understand this, because in both cases the Visible property
receives the same text value, "true". Any suggestions or ideas will be
greatly appreciated.

Thanks,

Keith

[Cowboy \(Gregory A. Beamer\)]

It is seeing "true" (string) not true (boolean), or visa versa. You will
have to cast out the value as the correct type. Easiest way is to alter the
SQL Statement that creates the value and cast there, as you will not have to
change your binding at all.

--
Gregory A. Beamer
MVP; MCP: +I, SE, SD, DBA

*************** *************** *************** ****
Think outside of the box!
*************** *************** *************** ****
"keithb" <kb******@dslex treme.comwrote in message
news:%2******** ********@TK2MSF TNGP02.phx.gbl. ..

Using a GridView, I get a "Specified cast is not valid" error when binding
the Visible propery of a hyperlink control to a DataTable text field. The
error goes away if I replace the data binding statement with "true" or
"false". This code causes the error:

<asp:HyperLin k ID="HyperLink1 "
runat="server"
NavigateUrl='<% #
Eval("c2Hyperli nk1Link") %>'
Target="_blank"
Text='<%#
Eval("c2Hyperli nk1Text") %>'
Visible='<%#
Eval("c2Hyperli nk1Visible") %>' ></asp:HyperLink>

This code runs without error:

<asp:HyperLin k ID="HyperLink1 "
runat="server"
NavigateUrl='<% #
Eval("c2Hyperli nk1Link") %>'
Target="_blank"
Text='<%#
Eval("c2Hyperli nk1Text") %>'
Visible="true" >'

</asp:HyperLink>

I do not understand this, because in both cases the Visible property
receives the same text value, "true". Any suggestions or ideas will be
greatly appreciated.

Thanks,

Keith

[Sergey Zuyev]

What if your data column has value of Null?
Make sure you are getting True/False value out of database.

Try convert value to Boolean explicitly

Visible='<%#
Ctype(Eval("c2H yperlink1Visibl e"), Boolean) %>' ></asp:HyperLink>

--
Programmer
"keithb" wrote:

Using a GridView, I get a "Specified cast is not valid" error when binding
the Visible propery of a hyperlink control to a DataTable text field. The
error goes away if I replace the data binding statement with "true" or
"false". This code causes the error:

<asp:HyperLin k ID="HyperLink1 "
runat="server"
NavigateUrl='<% #
Eval("c2Hyperli nk1Link") %>'
Target="_blank"
Text='<%#
Eval("c2Hyperli nk1Text") %>'
Visible='<%#
Eval("c2Hyperli nk1Visible") %>' ></asp:HyperLink>

This code runs without error:

<asp:HyperLin k ID="HyperLink1 "
runat="server"
NavigateUrl='<% #
Eval("c2Hyperli nk1Link") %>'
Target="_blank"
Text='<%#
Eval("c2Hyperli nk1Text") %>'
Visible="true" >'

></asp:HyperLink>

I do not understand this, because in both cases the Visible property
receives the same text value, "true". Any suggestions or ideas will be
greatly appreciated.

Thanks,

Keith

[keithb]

The data comes from a DataTable that is defined by an XSD file. I see no way
of defining the data field as Boolean. It looks like all of the fields are
text.

Thanks,

Keith
"Cowboy (Gregory A. Beamer)" <No************ @comcast.netNoS pamMwrote in
message news:eX******** ******@TK2MSFTN GP04.phx.gbl...

It is seeing "true" (string) not true (boolean), or visa versa. You will
have to cast out the value as the correct type. Easiest way is to alter
the SQL Statement that creates the value and cast there, as you will not
have to change your binding at all.

--
Gregory A. Beamer
MVP; MCP: +I, SE, SD, DBA

*************** *************** *************** ****
Think outside of the box!
*************** *************** *************** ****
"keithb" <kb******@dslex treme.comwrote in message
news:%2******** ********@TK2MSF TNGP02.phx.gbl. ..

>Using a GridView, I get a "Specified cast is not valid" error when
binding the Visible propery of a hyperlink control to a DataTable text
field. The error goes away if I replace the data binding statement with
"true" or "false". This code causes the error:

<asp:HyperLi nk ID="HyperLink1 "
runat="server"
NavigateUrl='<% #
Eval("c2Hyperl ink1Link") %>'
Target="_blank"
Text='<%#
Eval("c2Hyperl ink1Text") %>'
Visible='<%#
Eval("c2Hyperl ink1Visible") %>' ></asp:HyperLink>

This code runs without error:

<asp:HyperLi nk ID="HyperLink1 "
runat="server"
NavigateUrl='<% #
Eval("c2Hyperl ink1Link") %>'
Target="_blank"
Text='<%#
Eval("c2Hyperl ink1Text") %>'
Visible="true" >'

></asp:HyperLink>

I do not understand this, because in both cases the Visible property
receives the same text value, "true". Any suggestions or ideas will be
greatly appreciated.

Thanks,

Keith