Gridview row editing - dynamic binding to a DropDownList

Question

I m trying to get an ASP NET 3 5 GridView to show a selected value as string when being displayed  and to show a DropDownList to allow me to pick a value from a given list of options when being edited  Seems simple enough   My gridview looks like this  simplified     lt asp GridView ID  grvSecondaryLocations  runat  server                 DataKeyNames  ID  OnInit  grvSecondaryLocations Init                 OnRowCommand  grvSecondaryLocations RowCommand                 OnRowCancelingEdit  grvSecondaryLocations RowCancelingEdit                OnRowDeleting  grvSecondaryLocations RowDeleting                OnRowEditing  grvSecondaryLocations RowEditing                 OnRowUpdating  grvSecondaryLocations RowUpdating    gt   lt Columns gt       lt asp TemplateField gt            lt ItemTemplate gt                 lt asp Label ID  lblPbxTypeCaption  runat  server                                    Text   lt    Eval  PBXTypeCaptionValue     gt     gt            lt  ItemTemplate gt            lt EditItemTemplate gt                         lt asp DropDownList ID  ddlPBXTypeNS  runat  server                                  Width  200px                                  DataTextField  CaptionValue                                  DataValueField  OID    gt            lt  EditItemTemplate gt       lt  asp TemplateField gt   lt  asp GridView gt    The grid gets displayed OK when not in editing mode - the selected PBX type shows its value in the asp Label control  No surprise there   I load the list of values for the DropDownList into a local member called  pbxTypes in the OnLoad event of the form  I verified this - it works  the values are there   Now my challenge is  when the grid goes into editing mode for a particular row  I need to bind the list of PBX s stored in  pbxTypes    Simple enough  I thought - just grab the drop down list object in the RowEditing event and attach the list   protected void grvSecondaryLocations RowEditing object sender  GridViewEditEventArgs e        grvSecondaryLocations EditIndex   e NewEditIndex       GridViewRow editingRow   grvSecondaryLocations Rows e NewEditIndex        DropDownList ddlPbx    editingRow FindControl  ddlPBXTypeNS   as DropDownList       if  ddlPbx    null                ddlPbx DataSource    pbxTypes          ddlPbx DataBind                     more stuff      Trouble is - I never get anything back from the FindControl call - seems like the ddlPBXTypeNS doesn t exist  or can t be found    What am I missing   Must be something really stupid     but so far  all my Googling  reading up on GridView controls  and asking buddies hasn t helped   Who can spot the missing link   -

User · Answer

lt asp GridView ID  GridView1  runat  server  PageSize  2  AutoGenerateColumns  false              AllowPaging  true  BackColor  White  BorderColor   CC9966  BorderStyle  None              BorderWidth  1px  CellPadding  4  OnRowEditing  GridView1 RowEditing  OnRowUpdating  GridView1 RowUpdating              OnPageIndexChanging  GridView1 PageIndexChanging  OnRowCancelingEdit  GridView1 RowCancelingEdit              OnRowDeleting  GridView1 RowDeleting  gt               lt FooterStyle BackColor   FFFFCC  ForeColor   330099    gt               lt RowStyle BackColor  White  ForeColor   330099    gt               lt SelectedRowStyle BackColor   FFCC66  Font-Bold  True  ForeColor   663399    gt               lt PagerStyle BackColor   FFFFCC  ForeColor   330099  HorizontalAlign  Center    gt               lt HeaderStyle BackColor   990000  Font-Bold  True  ForeColor   FFFFCC    gt               lt Columns gt               lt asp TemplateField HeaderText  SerialNo  gt               lt ItemTemplate gt               lt    Container  DataItemIndex 1   gt   amp nbsp              lt  ItemTemplate gt               lt  asp TemplateField gt                   lt asp TemplateField HeaderText  RollNo  gt                       lt ItemTemplate gt                           lt  -- lt asp Label ID  lblrollno  runat  server  Text   lt   Eval   RollNo    gt   gt  lt  asp Label gt --  gt                           lt asp TextBox ID  txtrollno  runat  server  Text   lt   Eval   RollNo    gt   gt  lt  asp TextBox gt                       lt  ItemTemplate gt                   lt  asp TemplateField gt                   lt asp TemplateField HeaderText  SName  gt                       lt ItemTemplate gt                       lt  -- lt asp Label ID  lblsname  runat  server  Text   lt   Eval  SName    gt   gt  lt  asp Label gt --  gt                           lt asp TextBox ID  txtsname  runat  server  Text   lt   Eval  SName    gt   gt   lt  asp TextBox gt                       lt  ItemTemplate gt                   lt  asp TemplateField gt                   lt asp TemplateField HeaderText  C  gt                       lt ItemTemplate gt                       lt  --  lt asp Label ID  lblc  runat  server  Text   lt   Eval   C     gt   gt  lt  asp Label gt --  gt                           lt asp TextBox ID  txtc  runat  server  Text   lt   Eval   C     gt   gt  lt  asp TextBox gt                       lt  ItemTemplate gt                   lt  asp TemplateField gt                   lt asp TemplateField HeaderText  Cpp  gt                       lt ItemTemplate gt                       lt  --  lt asp Label ID  lblcpp  runat  server  Text   lt   Eval   Cpp    gt   gt  lt  asp Label gt --  gt                          lt asp TextBox ID  txtcpp  runat  server  Text   lt   Eval   Cpp    gt   gt   lt  asp TextBox gt                       lt  ItemTemplate gt                   lt  asp TemplateField gt                   lt asp TemplateField HeaderText  Java  gt                       lt ItemTemplate gt                          lt  --   lt asp Label ID  lbljava  runat  server  Text   lt   Eval   Java    gt   gt   lt  asp Label gt --  gt                           lt asp TextBox ID  txtjava  runat  server  Text   lt   Eval   Java    gt   gt   lt  asp TextBox gt                       lt  ItemTemplate gt                   lt  asp TemplateField gt                   lt asp TemplateField HeaderText  Edit  ShowHeader  False  gt                       lt EditItemTemplate gt                           lt asp LinkButton ID  lnkbtnUpdate  runat  server  CausesValidation  true  Text  Update                              CommandName  Update  gt  lt  asp LinkButton gt                           lt asp LinkButton ID  lnkbtnCancel  runat  server  CausesValidation  false  Text  Cancel                              CommandName  Cancel  gt  lt  asp LinkButton gt                       lt  EditItemTemplate gt                       lt ItemTemplate gt                           lt asp LinkButton ID  btnEdit  runat  server  CausesValidation  false  CommandName  Edit                              Text  Edit  gt  lt  asp LinkButton gt                       lt  ItemTemplate gt                   lt  asp TemplateField gt                   lt asp CommandField HeaderText  Delete  ShowDeleteButton  True  ShowHeader  True    gt                   lt asp CommandField HeaderText  Select  ShowSelectButton  True  ShowHeader  True    gt               lt  Columns gt           lt  asp GridView gt           lt table gt               lt tr gt                   lt td gt                       lt asp Label ID  lblrollno  runat  server  Text  RollNo  gt  lt  asp Label gt                       lt asp TextBox ID  txtrollno  runat  server  gt  lt  asp TextBox gt                   lt  td gt                   lt td gt                       lt asp Label ID  lblsname  runat  server  Text  SName  gt  lt  asp Label gt                       lt asp TextBox ID  txtsname  runat  server  gt  lt  asp TextBox gt                   lt  td gt                   lt td gt                       lt asp Label ID  lblc  runat  server  Text  C  gt  lt  asp Label gt                       lt asp TextBox ID  txtc  runat  server  gt  lt  asp TextBox gt                   lt  td gt                   lt td gt                       lt asp Label ID  lblcpp  runat  server  Text  Cpp  gt  lt  asp Label gt                       lt asp TextBox ID  txtcpp  runat  server  gt  lt  asp TextBox gt                   lt  td gt                   lt td gt                       lt asp Label ID  lbljava  runat  server  Text  Java  gt  lt  asp Label gt                       lt asp TextBox ID  txtjava  runat  server  gt  lt  asp TextBox gt                   lt  td gt               lt  tr gt               lt tr gt                   lt td gt                       lt asp Button ID  Submit  runat  server  Text  Submit  OnClick  Submit Click    gt                       lt asp Button ID  Reset  runat  server  Text  Reset  OnClick  Reset Click    gt                   lt  td gt               lt  tr gt           lt  table gt

User · Answer

Quite easy    You re doing it wrong  because by that event the control is not there   protected void gv RowDataBound object sender  GridViewRowEventArgs e        if  e Row RowType    DataControlRowType DataRow  amp  amp            e Row RowState  amp  DataControlRowState Edit     DataControlRowState Edit                    Here you will get the Control you need like          DropDownList dl    DropDownList e Row FindControl  ddlPBXTypeNS              That is  it will only be valid for a DataRow  the actually row with data   and if it s in Edit mode    because you only edit one row at a time  The e Row FindControl  ddlPBXTypeNS   will only find the control that you want

User · Answer

I am using a ListView instead of a GridView in 3 5  When the user wants to edit I have set the selected item of the dropdown to the exising value of that column for the record  I am able to access the dropdown in the ItemDataBound event  Here s the code   protected void listViewABC ItemDataBound object sender  ListViewItemEventArgs e           This stmt is used to execute the code only in case of edit      if    ListView  sender   EditIndex    -1  amp  amp    ListViewDataItem  e Item   DisplayIndex      ListView  sender   EditIndex                  DropDownList  e Item FindControl  ddlXType     SelectedValue     MyClass   ListViewDataItem e Item  DataItem  XTypeId ToString              DropDownList  e Item FindControl  ddlIType     SelectedValue     MyClass   ListViewDataItem e Item  DataItem  ITypeId ToString

User · Answer

You can use SelectedValue    lt EditItemTemplate gt       lt asp DropDownList ID  ddlPBXTypeNS                        runat  server                        Width  200px                        DataSourceID  YDS                        DataTextField  CaptionValue                        DataValueField  OID                        SelectedValue   lt    Bind  YourForeignKey     gt     gt       lt asp YourDataSource ID  YDS         gt   lt  EditItemTemplate gt

User · Answer

protected void grvSecondaryLocations RowEditing object sender  GridViewEditEventArgs e            grvSecondaryLocations EditIndex   e NewEditIndex         DropDownList ddlPbx    DropDownList  grvSecondaryLocations Rows grvSecondaryLocations EditIndex  FindControl  ddlPBXTypeNS         if  ddlPbx    null                    ddlPbx DataSource    pbxTypes            ddlPbx DataBind                         more stuff

User · Answer

The checked answer from balexandre works great   But  it will create a problem if adapted to some other situations   I used it to change the value of two label controls - lblEditModifiedBy and lblEditModifiedOn - when I was editing a row  so that the correct ModifiedBy and ModifiedOn would be saved to the db on  Update    When I clicked the  Update  button  in the RowUpdating event it showed the new values I entered in the OldValues list  I needed the true  old values  as Original  values when updating the database    There s an ObjectDataSource attached to the GridView    The fix to this is using balexandre s code  but in a modified form in the gv DataBound event   protected void gv DataBound object sender  EventArgs e        foreach  GridViewRow gvr in gv Rows                if  gvr RowType    DataControlRowType DataRow  amp  amp   gvr RowState  amp  DataControlRowState Edit     DataControlRowState Edit                           Here you will get the Control you need like                Label gvr FindControl  lblEditModifiedBy    Text   Page User Identity Name                Label gvr FindControl  lblEditModifiedOn    Text   DateTime Now ToString

[asp.net] Gridview row editing - dynamic binding to a DropDownList

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