problem extending a webcontrol

  • Thread starter Thread starter SoftLion
  • Start date Start date
S

SoftLion

Hi,
I've created a default asp.net web page and dragged a DataGrid inside it.
I would like to create a simple custom class derived from DataGrid to hide
all relevant code in it, instead of putting the code (especially for the
events) in the _default class.

This class is called DGMGrid2. I replaced the declaration :
protected System.Web.UI.WebControls.DataGrid DataGrid1;
with
protected DGMGrid2 DataGrid1;

public class DGMGrid2 : System.Web.UI.WebControls.DataGrid
{
public void DMGrid2() {}
}

That should work ?
It compiles OK but when executed there is a parse error:

Parser Error Message: The base class includes the field 'DataGrid1', but its
type (Foo.DGMGrid2) is not compatible with the type of control
(System.Web.UI.WebControls.DataGrid).
Error:
Line 20: <ASP:DATAGRID enableviewstate="false" id="DataGrid1"
runat="server" showfooter="False" width="100" cellpadding="2" pagesize="100"
autogeneratecolumns="False" horizontalalign="Center">

What is the right way to do that ?
Thanks !!
 
SoftLion said:
Hi,
I've created a default asp.net web page and dragged a DataGrid inside it.
I would like to create a simple custom class derived from DataGrid to hide
all relevant code in it, instead of putting the code (especially for the
events) in the _default class.

This class is called DGMGrid2. I replaced the declaration :
protected System.Web.UI.WebControls.DataGrid DataGrid1;
with
protected DGMGrid2 DataGrid1;

public class DGMGrid2 : System.Web.UI.WebControls.DataGrid
{
public void DMGrid2() {}
}

That should work ?
It compiles OK but when executed there is a parse error:

Parser Error Message: The base class includes the field 'DataGrid1', but its
type (Foo.DGMGrid2) is not compatible with the type of control
(System.Web.UI.WebControls.DataGrid).
Error:
Line 20: <ASP:DATAGRID enableviewstate="false" id="DataGrid1"
runat="server" showfooter="False" width="100" cellpadding="2" pagesize="100"
autogeneratecolumns="False" horizontalalign="Center">

What is the right way to do that ?
Click to expand...

Your .aspx page is referencing an ASP.NET DataGrid (type
System.Web.UI.WebControls.DataGrid), but you are actually using a DGMGrid2.
You should register your DGMGrid2 class (as "mine", for instance), then
reference "<mine:DMGrid2 ... />" in the .aspx page.

Also, remove the empty constructor. You don't want a return type in a
constructor, and the system-supplied default constructor will do the same
thing anyway.
 
Your .aspx page is referencing an ASP.NET DataGrid (type
System.Web.UI.WebControls.DataGrid), but you are actually using a DGMGrid2.
You should register your DGMGrid2 class (as "mine", for instance), then
reference "<mine:DMGrid2 ... />" in the .aspx page.
Click to expand...

Ok here is my new class:
public class DGMGrid2 : System.Web.UI.WebControls.DataGrid
{
}

And here is the Register directive:
<%@ Register TagPrefix="LocalGrid" Namespace="MyMainPage"
assembly="MyMainPage" %>

And here is the replacement tag :
<LocalGrid:DMGrid2 .... />

New error:
Could not load type MyMainPage.DMGrid2 from assembly MyMainPage,
Version=1.0.1627.25616, Culture=neutral, PublicKeyToken=null.

I don't want to create a nwe file for this class, nor a new special
assembly. I want to use the current page file. Any simple way to do this ?

Thks!
 
SoftLion said:
Ok here is my new class:
public class DGMGrid2 : System.Web.UI.WebControls.DataGrid
{
}

And here is the Register directive:
<%@ Register TagPrefix="LocalGrid" Namespace="MyMainPage"
assembly="MyMainPage" %>

And here is the replacement tag :
<LocalGrid:DMGrid2 .... />

New error:
Could not load type MyMainPage.DMGrid2 from assembly MyMainPage,
Version=1.0.1627.25616, Culture=neutral, PublicKeyToken=null.

I don't want to create a nwe file for this class, nor a new special
assembly. I want to use the current page file. Any simple way to do this ?
Click to expand...

Is your application called "MyMainPage"? If not, then that's not the right
name for the assembly. You need to specify the <appname>.dll file in your
bin folder.
 
Is your application called "MyMainPage"? If not, then that's not the right
name for the assembly. You need to specify the <appname>.dll file in your
bin folder.
Click to expand...

yes it is.
It appears there is no way to do this simply,
WebForms are just not as easy as MFC, ATL or WinForms.

B.
 
SoftLion said:
yes it is.
It appears there is no way to do this simply,
WebForms are just not as easy as MFC, ATL or WinForms.
Click to expand...

Ok, so you're saying there's a MyMainPage.dll in your bin directory?
 
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