Dropdownlist validation in Asp net Using Required field validator

Question

I have Dropdownlist whose value field and text field are bind at runtime  it has --select-- as first item with a value of 0 and the rest of the values are bind at runtime   I have given validaton group for both the control and the validator as  g1  and Intialvalue 0  But still the page is posting  back even if I select --select-- option    lt asp DropDownList AutoPostBack  true  CssClass  dropdown  ValidationGroup  g1       ID  ddlReportType  runat  server       OnSelectedIndexChanged  ddlReportType SelectedIndexChanged  gt  lt  asp DropDownList gt    lt asp RequiredFieldValidator ControlToValidate  ddlReportType  ID  RequiredFieldValidator1  ValidationGroup  g1  CssClass  errormesg  ErrorMessage  Please select a type  InitialValue  0  runat  server   Display  Dynamic  gt   lt  asp RequiredFieldValidator gt    And code Behind to Bind the Dropdown   ddlReportType Items Clear    ddlReportType DataSource   dt Tables 0   ddlReportType DataTextField    ReportType   ddlReportType DataValueField    ReportTypeID   ddlReportType DataBind    ddlReportType Items Insert 0  new ListItem  --Select--    0       ddlReportType Items 0  Value    0   ddlReportType SelectedIndex   0

User · Answer

Add InitialValue  0  in Required field validator tag    lt asp RequiredFieldValidator InitialValue  -1  ID  Req ID        Display  Dynamic  ValidationGroup  g1  runat  server        ControlToValidate  ControlID        InitialValue  0  ErrorMessage  ErrorMessage  gt    lt  asp RequiredFieldValidator gt

User · Answer

lt asp RequiredFieldValidator InitialValue  -1  ID  Req ID  Display  Dynamic       ValidationGroup  g1  runat  server  ControlToValidate  ControlID      Text     ErrorMessage  ErrorMessage  gt  lt  asp RequiredFieldValidator gt

User · Answer

I was struggling with this for a few days until I chanced on the issue when I had to build a new Dropdown   I had several DropDownList controls and attempted to get validation working with no luck  One was databound and the other was filled from the aspx page  I needed to drop the databound one and add a second manual list  In my case Validators failed if you built a dropdown like this and looked at any value  0 or -1  for either a required or compare validator    lt asp DropDownList ID  DDL Reason  CssClass  inputDropDown  runat  server  gt   lt asp ListItem gt --Select-- lt  asp ListItem gt                                                                                                   lt asp ListItem gt Expired lt  asp ListItem gt                                                                                                   lt asp ListItem gt Lost Stolen lt  asp ListItem gt                                                                                                   lt asp ListItem gt Location Change lt  asp ListItem gt                                                                                               lt  asp DropDownList gt    However adding the InitialValue like this worked instantly for a compare Validator    lt asp ListItem Text  -- Select --  Value  -1  gt  lt  asp ListItem gt

User · Answer

Here use asp CompareValidator  and compare the value to  select  option    Use Operator  NotEqual  ValueToCompare  0  to prevent the user from submitting the  select     lt asp CompareValidator ControlToValidate  ddlReportType  ID  CompareValidator1      ValidationGroup  g1  CssClass  errormesg  ErrorMessage  Please select a type      runat  server  Display  Dynamic       Operator  NotEqual  ValueToCompare  0  Type  Integer    gt    When you do above  if you select the  select   option from dropdown it will show the ErrorMessage

[asp.net] Dropdownlist validation in Asp.net Using Required field validator

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