GridView. What is wrong with my code? Thank You.

[shapper]

Hello,

I need to loop though each row in a GridView and if the checkbox is a
Template Field is checked I want to display the value of an invisible
column named "LevelName" .

I tried everything I could think off but I always get an error or no
value.
Could someone please let me know what might be wrong?

Here is my GridView init code:

1 Private Sub gvLevels_Init(B yVal sender As Object, ByVal e As
System.EventArg s) Handles gvLevels.Init
2
3 With gvLevels
4 .AutoGenerateCo lumns = False
5 .DataKeyNames = New String() {"LevelName" }
6 .DataSource = Levels_Fill()
7 .ID = "gvLevels"
8 End With
9
10 Dim bfLevelDescript ion As New BoundField
11 bfLevelDescript ion.DataField = "LevelDescripti on"
12 gvLevels.Column s.Add(bfLevelDe scription)
13
14 Dim tfLevelSubscrip tion As New TemplateField
15 tfLevelSubscrip tion.ItemTempla te = New
tfLevelSubscrip tion(ListItemTy pe.Item)
16 gvLevels.Column s.Add(tfLevelSu bscription)
17
18 gvLevels.DataBi nd()
19
20 End Sub ' gvLevels_Init

My grid view data source is:

1 Private Function Levels_Fill() As DataView
2
3 Dim dtLevels As New DataTable("Leve ls")
4 Dim dvLevels As DataView
5 dtLevels = Levels.GetAllLe vels().Tables(0 )
6 dtLevels.Column s.Add(New DataColumn("Lev elSubscription" ,
GetType(Boolean )))
7
8 ' Define dtLevels primary key
9 dtLevels.Primar yKey = New DataColumn()
{dtLevels.Colum ns("LevelName") }
10
11 dvLevels = New DataView(dtLeve ls, "", "LevelName" ,
DataViewRowStat e.CurrentRows)
12 Return dvLevels
13
14 End Function ' Levels_Fill

I am trying to access my check boxes as follows:

1 Dim dkLevel As DataKey
2 For Each gvrLevel As GridViewRow In gvLevels.Rows
3 Dim cbLevelSubscrip tion As CheckBox =
CType(gvrLevel. FindControl("cb LevelSubscripti on"), CheckBox)
4 If cbLevelSubscrip tion.Checked Then
5 dkLevel = gvLevels.DataKe ys(gvrLevel.Row Index)
6 Response.Write( dkLevel.Value)
7 End If
8 Next gvrLevel

When I click the button which will run the code that loops through
each check box I get the following error:

"Item has already been added.Key in dictionay: "LevelName" Key been
added: "LevelName"

I removed:

5 .DataKeyNames = New String() {"LevelName" }

And I stopped having this error but still does not work.

Any idea?

Thanks,

Miguel

[Roland Dick]

Hello Miguel,

Is it possible that your sub gvLevels_Init is being called several
times? (Maybe on each Page_Load without checking for a PostBack?)

If you remove setting the DataKeyNames property, then I don't think
gvLevels.DataKe ys(gvrLevel.Row Index) will return anything.

My advice would be: Set a breakpoint in the gvLevels_Init sub and make
sure it's only hit the first time the page loads, and "never" again
after that (and especially not when hitting the button that evaluates
the checkboxes!)

Hope this helps,

Cheers,

Roland

shapper schrieb:

Hello,

I need to loop though each row in a GridView and if the checkbox is a
Template Field is checked I want to display the value of an invisible
column named "LevelName" .

I tried everything I could think off but I always get an error or no
value.
Could someone please let me know what might be wrong?

Here is my GridView init code:

1 Private Sub gvLevels_Init(B yVal sender As Object, ByVal e As
System.EventArg s) Handles gvLevels.Init
2
3 With gvLevels
4 .AutoGenerateCo lumns = False
5 .DataKeyNames = New String() {"LevelName" }
6 .DataSource = Levels_Fill()
7 .ID = "gvLevels"
8 End With
9
10 Dim bfLevelDescript ion As New BoundField
11 bfLevelDescript ion.DataField = "LevelDescripti on"
12 gvLevels.Column s.Add(bfLevelDe scription)
13
14 Dim tfLevelSubscrip tion As New TemplateField
15 tfLevelSubscrip tion.ItemTempla te = New
tfLevelSubscrip tion(ListItemTy pe.Item)
16 gvLevels.Column s.Add(tfLevelSu bscription)
17
18 gvLevels.DataBi nd()
19
20 End Sub ' gvLevels_Init

My grid view data source is:

1 Private Function Levels_Fill() As DataView
2
3 Dim dtLevels As New DataTable("Leve ls")
4 Dim dvLevels As DataView
5 dtLevels = Levels.GetAllLe vels().Tables(0 )
6 dtLevels.Column s.Add(New DataColumn("Lev elSubscription" ,
GetType(Boolean )))
7
8 ' Define dtLevels primary key
9 dtLevels.Primar yKey = New DataColumn()
{dtLevels.Colum ns("LevelName") }
10
11 dvLevels = New DataView(dtLeve ls, "", "LevelName" ,
DataViewRowStat e.CurrentRows)
12 Return dvLevels
13
14 End Function ' Levels_Fill

I am trying to access my check boxes as follows:

1 Dim dkLevel As DataKey
2 For Each gvrLevel As GridViewRow In gvLevels.Rows
3 Dim cbLevelSubscrip tion As CheckBox =
CType(gvrLevel. FindControl("cb LevelSubscripti on"), CheckBox)
4 If cbLevelSubscrip tion.Checked Then
5 dkLevel = gvLevels.DataKe ys(gvrLevel.Row Index)
6 Response.Write( dkLevel.Value)
7 End If
8 Next gvrLevel

When I click the button which will run the code that loops through
each check box I get the following error:

"Item has already been added.Key in dictionay: "LevelName" Key been
added: "LevelName"

I removed:

5 .DataKeyNames = New String() {"LevelName" }

And I stopped having this error but still does not work.

Any idea?

Thanks,

Miguel

[shapper]

On Mar 13, 11:48 pm, Roland Dick <[e-mail] wrote:

Hello Miguel,

Is it possible that your sub gvLevels_Init is being called several
times? (Maybe on each Page_Load without checking for a PostBack?)

If you remove setting the DataKeyNames property, then I don't think
gvLevels.DataKe ys(gvrLevel.Row Index) will return anything.

My advice would be: Set a breakpoint in the gvLevels_Init sub and make
sure it's only hit the first time the page loads, and "never" again
after that (and especially not when hitting the button that evaluates
the checkboxes!)

Hope this helps,

Cheers,

Roland

shapper schrieb:

Hello,

I need to loop though each row in a GridView and if the checkbox is a
Template Field is checked I want to display the value of an invisible
column named "LevelName" .

I tried everything I could think off but I always get an error or no
value.
Could someone please let me know what might be wrong?

Here is my GridView init code:

1 Private Sub gvLevels_Init(B yVal sender As Object, ByVal e As
System.EventArg s) Handles gvLevels.Init
2
3 With gvLevels
4 .AutoGenerateCo lumns = False
5 .DataKeyNames = New String() {"LevelName" }
6 .DataSource = Levels_Fill()
7 .ID = "gvLevels"
8 End With
9
10 Dim bfLevelDescript ion As New BoundField
11 bfLevelDescript ion.DataField = "LevelDescripti on"
12 gvLevels.Column s.Add(bfLevelDe scription)
13
14 Dim tfLevelSubscrip tion As New TemplateField
15 tfLevelSubscrip tion.ItemTempla te = New
tfLevelSubscrip tion(ListItemTy pe.Item)
16 gvLevels.Column s.Add(tfLevelSu bscription)
17
18 gvLevels.DataBi nd()
19
20 End Sub ' gvLevels_Init

My grid view data source is:

1 Private Function Levels_Fill() As DataView
2
3 Dim dtLevels As New DataTable("Leve ls")
4 Dim dvLevels As DataView
5 dtLevels = Levels.GetAllLe vels().Tables(0 )
6 dtLevels.Column s.Add(New DataColumn("Lev elSubscription" ,
GetType(Boolean )))
7
8 ' Define dtLevels primary key
9 dtLevels.Primar yKey = New DataColumn()
{dtLevels.Colum ns("LevelName") }
10
11 dvLevels = New DataView(dtLeve ls, "", "LevelName" ,
DataViewRowStat e.CurrentRows)
12 Return dvLevels
13
14 End Function ' Levels_Fill

I am trying to access my check boxes as follows:

1 Dim dkLevel As DataKey
2 For Each gvrLevel As GridViewRow In gvLevels.Rows
3 Dim cbLevelSubscrip tion As CheckBox =
CType(gvrLevel. FindControl("cb LevelSubscripti on"), CheckBox)
4 If cbLevelSubscrip tion.Checked Then
5 dkLevel = gvLevels.DataKe ys(gvrLevel.Row Index)
6 Response.Write( dkLevel.Value)
7 End If
8 Next gvrLevel

When I click the button which will run the code that loops through
each check box I get the following error:

"Item has already been added.Key in dictionay: "LevelName" Key been
added: "LevelName"

I removed:

5 .DataKeyNames = New String() {"LevelName" }

And I stopped having this error but still does not work.

Any idea?

Thanks,

Miguel

Hi Roland,

I did what you suggested and the code line .DataKeyNames = New
String() {"LevelName" } was running when page started and when the
button was clicked.
So I moved the code line to:

' gvLevels_Load
Private Sub gvLevels_Load(B yVal sender As Object, ByVal e As
System.EventArg s) Handles gvLevels.Load

If Not Page.IsPostBack Then gvLevels.DataKe yNames = New String()
{"LevelName" }

End Sub ' gvLevels_Load

Inside the loop which goes through each GridView row I placed:

Response.Write( gvrLevel.RowInd ex.ToString)

Response.Write( gvLevels.DataKe ys(gvrLevel.Row Index.ToString) .Value.ToString ())
****

Now I get an exception on code line ****:
System.Argument OutOfRangeExcep tion: Index was out of range. Must be
non-negative and less than the size of the collection. Parameter name:
index at System.Collecti ons.ArrayList.g et_Item(Int32 index) at
System.Web.UI.W ebControls.Data KeyArray.get_It em(Int32 index) at ...

Any idea why?

Thanks,
Miguel

[Roland Dick]

Hi Miguel,

the following code works for me (it is C# as it is my preferred
language, but I'm sure you get the principles):

protected void Page_Load(objec t sender, EventArgs e)
{
if (!this.IsPostBa ck)
{
this.GridView1. DataSource = GetDataSource() ;
this.GridView1. DataKeyNames = new string[] {
"LevelValue " };
this.GridView1. DataBind();
}
}

protected DataSet GetDataSource()
{
DataSet ds = new DataSet();
DataTable dt = ds.Tables.Add() ;
dt.Columns.Add( "LevelValue ");
dt.Columns.Add( "LevelText" );
dt.Rows.Add(new object[] { 1, "One" });
dt.Rows.Add(new object[] { 2, "Two" });
dt.Rows.Add(new object[] { 3, "Three" });
return ds;
}

protected void Button1_Click(o bject sender, EventArgs e)
{
this.lblSelecte dValues.Text = "";
foreach (GridViewRow row in this.GridView1. Rows)
{
CheckBox c = row.FindControl ("chkSelecte d") as CheckBox;
if (c != null)
{
if (c.Checked)
{
DataKey dk =
this.GridView1. DataKeys[row.DataItemInd ex];
if (dk != null)
this.lblSelecte dValues.Text +=
dk.Value.ToStri ng() + ", ";
}
}
}
}
And in the aspx:

<asp:GridView ID="GridView1" runat="server" AutoGenerateCol umns="False">
<Columns>
<asp:TemplateFi eld>
<ItemTemplate >
<asp:CheckBox ID="chkSelected " runat="server" />
</ItemTemplate>
</asp:TemplateFie ld>
<asp:BoundFie ld DataField="Leve lValue" Visible="False" />
<asp:BoundFie ld DataField="Leve lText" />
</Columns>
</asp:GridView>
<asp:Button ID="Button1" runat="server" OnClick="Button 1_Click"
Text="Button" />
<br />
<asp:Label ID="lblSelected Values" runat="server"
Text="Label"></asp:Label>
The field names are bit different to yours, but the logic should be the
same.

Hope this helps,

Roland

shapper schrieb:

I did what you suggested and the code line .DataKeyNames = New
String() {"LevelName" } was running when page started and when the
button was clicked.
So I moved the code line to:

' gvLevels_Load
Private Sub gvLevels_Load(B yVal sender As Object, ByVal e As
System.EventArg s) Handles gvLevels.Load

If Not Page.IsPostBack Then gvLevels.DataKe yNames = New String()
{"LevelName" }

End Sub ' gvLevels_Load

Inside the loop which goes through each GridView row I placed:

Response.Write( gvrLevel.RowInd ex.ToString)

Response.Write( gvLevels.DataKe ys(gvrLevel.Row Index.ToString) .Value.ToString ())
****

Now I get an exception on code line ****:
System.Argument OutOfRangeExcep tion: Index was out of range. Must be
non-negative and less than the size of the collection. Parameter name:
index at System.Collecti ons.ArrayList.g et_Item(Int32 index) at
System.Web.UI.W ebControls.Data KeyArray.get_It em(Int32 index) at ...

Any idea why?

Thanks,
Miguel