Listview ItemCommand - Having a problem with my first listview Itemcommand.

Question

User-1999980185 posted

Please review the below Code, HTML, and Error message.  I got the example from a link and I am having a problem.

HTML Below:

 <asp:ListView ID="ListView1" runat="server" OnItemCommand="ListView1_ItemCommand" CommandArgument="<%# Container.DataItemIndex %>">

Code Below:

 protected void ListView1_ItemCommand(object sender, ListViewCommandEventArgs e)
        {
            // FindConrol code goes here
            Label LblDDate = ListView1.Item[e.commandArgument].findControl("DDate");   // <==== Error on this line

            // Determine what button was selected
            if (string.Equals(e.CommandName, "Select_Sel"))     // transfer to change page

            {

                Response.Redirect("form2_Chg.aspx");

            }
                               
        }


Error Below:

Severity	Code	Description	Project	File	Line	Suppression State
Error	CS1061	'FirstCWeb_PageOne' does not contain a definition for 'DataItemIndex' and no extension method 'DataItemIndex' accepting a first argument of type 'FirstCWeb_PageOne' could be found (are you missing a using directive or an assembly reference?)	FirstCWeb	C:\Users\Edward\documents\visual studio 2015\Projects\MyFirstCWeb_Solution\FirstCWeb\FirstCWeb_PageOne.aspx	30	Active

Severity	Code	Description	Project	File	Line	Suppression State
Error	CS1061	'ListView' does not contain a definition for 'Item' and no extension method 'Item' accepting a first argument of type 'ListView' could be found (are you missing a using directive or an assembly reference?)	FirstCWeb	C:\Users\Edward\documents\visual studio 2015\Projects\MyFirstCWeb_Solution\FirstCWeb\FirstCWeb_PageOne.aspx.cs	131	Active

Severity	Code	Description	Project	File	Line	Suppression State
Error	CS1061	'ListViewCommandEventArgs' does not contain a definition for 'commandArgument' and no extension method 'commandArgument' accepting a first argument of type 'ListViewCommandEventArgs' could be found (are you missing a using directive or an assembly reference?)	FirstCWeb	C:\Users\Edward\documents\visual studio 2015\Projects\MyFirstCWeb_Solution\FirstCWeb\FirstCWeb_PageOne.aspx.cs	131	Active

Answer 1

User283571144 posted

Hi [e-mail],

Error	CS1061	'FirstCWeb_PageOne' does not contain a definition for 'DataItemIndex' and no extension method 'DataItemIndex' accepting a first argument of type 'FirstCWeb_PageOne' could be found (are you missing a using directive or an assembly reference?)	FirstCWeb	C:\Users\Edward\documents\visual studio 2015\Projects\MyFirstCWeb_Solution\FirstCWeb\FirstCWeb_PageOne.aspx	30	Active

According to your description and error message, I found you add the CommandArgument directly in the listview control and bind the DataItemIndex in it.

Since the Container.DataItemIndex need inside ItemTemplate not directly in a listview.

So you faced this error.

I suggest you could set the property in a button control in listview’s  <ItemTemplate> section , so when you click the button , the event will be fired.

 

Severity	Code	Description	Project	File	Line	Suppression State
Error	CS1061	'ListView' does not contain a definition for 'Item' and no extension method 'Item' accepting a first argument of type 'ListView' could be found (are you missing a using directive or an assembly reference?)	FirstCWeb	C:\Users\Edward\documents\visual studio 2015\Projects\MyFirstCWeb_Solution\FirstCWeb\FirstCWeb_PageOne.aspx.cs	131	Active

Severity	Code	Description	Project	File	Line	Suppression State
Error	CS1061	'ListViewCommandEventArgs' does not contain a definition for 'commandArgument' and no extension method 'commandArgument' accepting a first argument of type 'ListViewCommandEventArgs' could be found (are you missing a using directive or an assembly reference?)	FirstCWeb	C:\Users\Edward\documents\visual studio 2015\Projects\MyFirstCWeb_Solution\FirstCWeb\FirstCWeb_PageOne.aspx.cs	131	Active

As far as I know, the ListView only has a definition for Items and your commandArgument  should be CommandArgument whose “C” is  upper-case.

More details, you could refer to below codes:

<asp:ListView ID="ListView1" runat="server" OnItemCommand="ListView1_ItemCommand" SelectMethod="GetSuppliers" ItemType="WebFormCases.Models.Supplier" >
 
            <ItemTemplate>
 
                <tr> 
 
                    <td>  <asp:Label ID="DDate" runat="server" Text="<%#Item.SID %>"></asp:Label></td>
                         <td>  <asp:Label ID="Label2" runat="server" Text="<%#Item.Name %>"></asp:Label></td>
                         <td>  <asp:Label ID="Label3" runat="server" Text="<%#Item.City %>"></asp:Label></td>
                    <td>  
                    <asp:Button ID="Button1" runat="server" Text="Button" CommandArgument="<%#Container.DataItemIndex %>" CommandName="Select_Sel" /></td>
                </tr>
 
            </ItemTemplate>
 
            <LayoutTemplate>
    
                        
                                    <table id="itemPlaceholderContainer" runat="server" style="width:100%">
                                        <tr id="itemPlaceholder"></tr>
                                    </table>
                          
                  
 
            </LayoutTemplate>
 
        </asp:ListView>
 

Code-behind:

protected void ListView1_ItemCommand(object sender, ListViewCommandEventArgs e)
        {
  Label LblDDate 
//you should convert object to int32 to get the item  and convert the finded control to Label
=ListView1.Items[Convert.ToInt32(e.CommandArgument)].FindControl("DDate") as Label ;    
            if (string.Equals(e.CommandName, "Select_Sel"))
 
            {
 
                Response.Redirect("form2_Chg.aspx");
 
            }
 
        }
 
        SupplyModel repo = new SupplyModel();
        public IQueryable<Supplier> GetSuppliers()
        {
            return repo.Suppliers.AsQueryable();
        }
}
 

Result:

Best Regards,

Brando

 

Answer 2

User-1999980185 posted

Brando, Thanks for your help. I am new in C# and I am just learning the basic please read the below new code and new error.
The next two statement work in VB and I would like to do the same in C#

Dim dataitem As ListViewDataItem = CType(e.Item, ListViewDataItem)
Dim lblddate As Label = ListView_Budget_todo.Items(dataitem.DisplayIndex).FindControl("ddate")

This is new code below:

        protected void ListView1_ItemCommand(object sender, ListViewCommandEventArgs e)
        {
            // FindConrol code goes here
            Label LblDDate = ListView1.findControl("DDate");

            // Determine what button was selected
            if (string.Equals(e.CommandName, "Select_Sel"))     // transfer to change page

            {

                Response.Redirect("form2_Chg.aspx");

            }

below is my new error:

Severity	Code	Description	Project	File	Line	Suppression State
Error	CS1061	'ListView' does not contain a definition for 'findControl' and no extension method 'findControl' accepting a first argument of type 'ListView' could be found (are you missing a using directive or an assembly reference?)	FirstCWeb	C:\Users\Edward\documents\visual studio 2015\Projects\MyFirstCWeb_Solution\FirstCWeb\FirstCWeb_PageOne.aspx.cs	131	Active

==============================================

Answer 3

User283571144 posted

Hi [e-mail],

Normally, the method in c# start with an upper-case character, so you should change “findControl” to FindControl.

If you are not familiar with an object’s method , you could rely on visual studio’s intellisense or use shortcut key ctrl+j .

Besides, we couldn't directly convert  ListView1.FindControl("DDate")'s result to label, since it is a control not label.

We should firstly conver the control to lable, then we could use it.

More details, you could refer to below codes:

            Label LblDDate = (Label)ListView1.FindControl("DDate");

Best Regards,

Brando

Answer 4

User-1999980185 posted

What changes should I make in the new code.   This is driving me crazy.  Thanks again for all your help.

Brando,  My button is a LINKBUTTOM not a BUTTOM do that make a difference?  Below is my new code, new markup and new error message.  Thanks for all your help.

New Error Below:
Severity	Code	Description	Project	File	Line	Suppression State
Error	CS0266	Cannot implicitly convert type 'System.Web.UI.Control' to 'System.Web.UI.WebControls.Label'. An explicit conversion exists (are you missing a cast?)	FirstCWeb	C:\Users\Edward\documents\visual studio 2015\Projects\MyFirstCWeb_Solution\FirstCWeb\FirstCWeb_PageOne.aspx.cs	131	Active

New Code Below:
 protected void ListView1_ItemCommand(object sender, ListViewCommandEventArgs e)
        {
            // FindConrol code goes here
            Label LblDDate = ListView1.FindControl("DDate");

            // Determine what button was selected
            if (string.Equals(e.CommandName, "Select_Sel"))     // transfer to change page

            {

                Response.Redirect("form2_Chg.aspx");

            }
                               
        }

New Markup Code Below:
            <td>
                      <asp:linkbutton ID="Linkbutton1" runat="server"  text='Select' Commandname="Select_Sel" />                   
                   </td>

                <td>
                      <asp:label ID="DDate" runat="server"  text='<%# Eval("DDate")%>' />                   
                  </td> 

Answer 5

User-1999980185 posted

OK, the problem is resolved.  I had to put a as Label; in the end of the code.   Thanks for all the help.  I am getting to learn C# the hard way.  Thanks again for the help.