I need to hide /unhide the labels and textbox depending on db results , I tried something like this but it doesnt works, the condition should be like if the db field is empty for that field , then the label associated with that field should hidden (not visible) , following is the code i tried :
<asp:Label ID="lblBirth" Text="DOB:" runat="server" ViewStateMode="Disabled" CssClass="lbl" />
<asp:Label ID="DOB" runat="server" CssClass="lblResult" Visible='<%# Eval("Berth") == DBNull.Value %>'></asp:Label>
Code behind:
protected void showDetails(int makeID)
{// get all the details of the selected caravan and populate the empty fields
DataTable dt = new DataTable();
DataTableReader dtr = caravans.GetCaravanDetailsByMakeID(makeID);
while (dtr.Read())
{
//spec
string value = dtr["Price"].ToString();
lblModel.Text = dtr["model"].ToString();
birthResult.Text = dtr["Berth"].ToString(); }}
To make your aspx version work your control should be data bound to data source that contains "Berth" property. As I can see from code behind, you prefer to use c# to populate controls. In this case you may just do the following:
DOB.Visible = dtr["Berth"] == DBNull.Value;
I think that using data binding is more preferable solution.
Related
I'm trying to show a value from a database into a asp:label. I can show the data into a dropdownlist but not into a asp:label.
This works:
<asp:DropDownList ID="code" runat="server" DataSourceID="onlymonths"
DataTextField="itemCode" DataValueField="itemCode">
</asp:DropDownList>
I have tried to do it as follows but no luck:
<asp:Label ID="code" runat="server" DataSourceID="onlymonths"
DataTextField="itemCode" DataValueField="itemCode">
</asp:Label>
So does anyone know how to show the value into the label?
asp labels are not databound controls like dropdownlists or gridviews, you would be better off writing a method to get at the data and populating the label manually something like this
using(SqlDataReader rdr = cmd.ExecuteReader())
{
while (rdr.Read())
{
mylablel.text = rdr.GetString(0);
}
}
You need to change id of code of lable to lblCode since your drop down list id is code
Then write the following code
lblCode.Text = code.SelectedItem.Text;
I have a grid that I need to add columns to dynamically (programatically).
I have been browsing Telerik forums as well as Google and im not able to find anything. Decompiling GridTemplateColumn shows that there should be ItemTemplate property however my VS throws an error.
Dim col As GridColumn = New GridButtonColumn()
col.UniqueName = stockLocation("LocationID").ToString()
col.HeaderText = stockLocation("Name").ToString()
col.ItemTemplate = ERROR HERE
rgGridCombinations.Columns.Add(col)
I'm trying to create a column that will look like following ASPX code.
<radg:GridTemplateColumn HeaderText="Stock" UniqueName="Stock" Visible="true" HeaderStyle-Width="10%">
<ItemTemplate>
<asp:TextBox ID="tbStock" runat="server" Width="100%" />
</ItemTemplate>
</radg:GridTemplateColumn>
How would I create this?
1) GridColumn does not have ItemTemplate property
2) You were assigning GridButtonColumn. Use GridTemplateColumn instead
Try this
Dim col = As New GridTemplateColumn()
col.UniqueName = "Stock"
col.HeaderText = "Stock"
col.ItemTemplate = <something here> 'should be an ITemplate
rgGridCombinations.Columns.Add(col)
For more information on how to create template, check here
In a web application I am binding the data to a GridView. In the GridView some of data is repeating. I want to not display the data again and again.
For example Empid is displaying more than one time in the same column. I want to not display the empid again in that column.
You can implement the OnDataBinding event for the specific column you are using. I never use AutoGenerateColumns so having fine control of each cell is pretty simple to implement.
Eg:
// Create global in your .cs file
string _currentEmpID = string.Empty;
Define your column like:
<Columns>
<asp:TemplateField>
<ItemTemplate>
<asp:Literal ID="ltEmpID" runat="server"
OnDataBinding="ltEmpID_DataBinding" />
</ItemTemplate>
</asp:TemplateField>
<!-- Your other columns... -->
</Columns>
Then just implement your DataBinding event:
protected void ltEmpID_DataBinding(object sender, System.EventArgs e)
{
Literal lt = (Literal)(sender);
string empID = Eval("EmpID").ToString();
if (!empID.Equals(_currentEmpID))
{
lt.Text = empID;
_currentEmpID = empID;
}
else
{
lt.Text = string.Empty;
}
}
The RowDataBound forces you to search for controls and if changes are required in the future you have the possibility of breaking other things being modified within the event. Because of this, I prefer to use the control's DataBinding event whenever possible as it localizes functionality to only the control and gives you the flexability to swap out controls and functionality easily without the worry off affecting other things.
If you group your data by the columns you don't want to repeat before binding it to your datasource you can bind an event to RowDataBound and check if the current value equals the previous and then hide the cell.
Check this for an example.
Just add the property AutoGenerateColumns in the gridview and assign it the value of false.
AutoGenerateColumns="false"
I have the following client side code in .aspx page within a datalist itemtemplate that takes questions from the database like this:
<Itemtemplate>
<b> <%=GetQuestionNum()%>)
<%#Server.HtmlEncode(Eval("Text").ToString())%></b>
<br />
<asp:Panel ID="A" runat="server" Visible='<%#GetVisible(Eval("OptionA").Tostring())%>'>
<input name="Q<%#Eval("ID")%>" type="radio" value="A">
<%#Server.HtmlEncode(Eval("OptionA").ToString())%>
</option><br />
</asp:Panel>
<asp:Panel ID="B" runat="server" Visible='<%#GetVisible(Eval("OptionB").Tostring())%>'>
<input name="Q<%#Eval("ID")%>" type="radio" value="B">
<%#Server.HtmlEncode(Eval("OptionB").ToString())%>
</option><br />
</asp:Panel>
<asp:Panel ID="C" runat="server" Visible='<%#GetVisible(Eval("OptionC").Tostring())%>'>
<input name="Q<%#Eval("ID")%>" type="radio" value="C">
<%#Server.HtmlEncode(Eval("OptionC").ToString())%>
</option><br />
</asp:Panel>
<asp:Panel ID="D" runat="server" Visible='<%#GetVisible(Eval("OptionD").Tostring())%>'>
<input name="Q<%#Eval("ID")%>" type="radio" value="D">
<%#Server.HtmlEncode(Eval("OptionD").ToString())%>
</option><br />
</asp:Panel></itemtemplate>
The output is like:
1) What is your age group?
- Option 1
- Option 2
- Option 3
- Option 4
The ID's of the radio buttons are dynamic ("Q" & QuestionID). If there is no answer to a question then the GetVisible function returns false and the containing panel is hidden.
I have been trying to get rid of the html and replace these with asp:radiobuttons but it is not possible to set id's from databinding.. only simply. I was trying something like:
<asp:RadioButton ID="Q<%#Eval("ID")%>" runat="server" Visible='<%#GetVisible(Eval("OptionA").Tostring())%>'
Text='<%#Server.HtmlEncode(Eval("OptionA").ToString())%>' />
Here is the function that provides data:
Public Shared Function GetQuestionsForSurvey(ByVal id As Integer) As DataSet
Dim dsQuestions As DataSet = New DataSet()
Try
Using mConnection As New SqlConnection(Config.ConnectionString)
Dim mCommand As SqlCommand = New SqlCommand("sprocQuestionSelectList", mConnection)
mCommand.CommandType = CommandType.StoredProcedure
Dim myDataAdapter As SqlDataAdapter = New SqlDataAdapter()
myDataAdapter.SelectCommand = mCommand
mCommand.CommandType = CommandType.StoredProcedure
mCommand.Parameters.AddWithValue("#id", id)
myDataAdapter.Fill(dsQuestions)
mConnection.Close()
Return dsQuestions
End Using
Catch ex As Exception
Throw
End Try
End Function
but I'm finding it impossible to work with the html controls, i.e get their .text value from codebehind, or adding events!
Please can an expert suggest a better way to replace the html with suitable asp.net web controls or from the codebehind and output it. Or point me in the right direction?
Thanks :0)
I had some experience with ASP controls and data binding. The problem you are facing is probably the fact that once you declare a control via markup you can't access it from data binding. Also, you should not confuse the server-side ID with the client-side ID.
The server-side ID, mapped to Id property of controls, is used to programmatically access the control from code behind. Client-side ID is the ID that will be placed in tag's id attribute and is mapped to ClientId property.
Judging from your question, what you need is to build a multi-choice survey, and, in my opinion, it's not important how the IDs are generated, just that they are properly grouped for each question.
I'll answer the part of programmatically accessing controls in data binding, which is a part of your question.
Here is an example from my code. Suppose you have a very simple GridView like this
<asp:GridView ID="example" runat="server" OnRowDataBound="DataBound">
<Columns>
<asp:TemplateField HeaderText="New">
<ItemTemplate>
<asp:Image ID="imgExample" runat="server" />
</ItemTemplate>
</Columns>
</asp:GridView>
It takes a data set during data binding and sets the image according to some property. It works the same as DataList, don't worry.
Now, in code behind, you handle the RowDataBoundEvent. You can't access the imgExample object directly, because it's a child of the ItemTemplate. When the row is bound, you have direct access to the row and then you can use the FindControl method of Control class
Here is C# code example (easy to convert to VB)
protected void DataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow) //Required
{
GridViewRow row = e.Row;
[...] //get an email message
(row.Cells[0].FindControl("imgExample") as Image).ImageUrl = (email.AlreadyRead)
? "Mail_Small.png"
: "Mail_New_Small.png";
}
}
Application to your case
In order to build a multi-choice survey, my advice is to create a DataList that will hold questions (the outer control) and then, for each row, declare a RadioButtonList that holds answers (the inner control). Bind the outer data list to the data set of questions and answers. Handle the RowDataBound event or whatever it's called in the DataList world. When you handle that event, bind the inner radiobuttonlist to the answers.
It should work for you
I am actually working on something similar at the moment. I am using javascript and jQuery to dynamically add controls to my page. After adding them to my page I have to get the new controls, their text, etc. The way I've been doing it is something like this:
<table id='BuilderTable' class="BuilderTable">
<tbody class='BuilderBody'>
</tbody>
</table>
<asp:Button runat="server" ID="saveButton" OnClick="SaveButton_Click" OnClientClick="SaveData()"
Text="Save Form" />
<asp:HiddenField runat="server" ID="controlsData" />
This table is where I put all my new controls.
Then when the client clicks the save button it first calls this javascript / jQuery function:
function SaveData() {
var controlRows = $('#BuilderTable tr.control');
var controls= [];
controlRows.each(function (index) {
//process control information here ...
controlText = //use jQuery to get text, etc...
var control = {
Index: (index + 1),
Text: controlText
};
controls.push(control);
});
var str = JSON.stringify(questions);
$('#<%= controlsData.ClientID %>').val(str);
}
Then the server side function for the button click is called (this in in C#, adapt to VB).
protected void SaveButton_Click(object sender, EventArgs e)
{
JavaScriptSerializer jss = new JavaScriptSerializer();
string str = controlsData.Value;
List<Control> controls = jss.Deserialize<List<Control>>(str);
}
Using a Control class like this:
public class Control
{
public int Index { get; set; }
public string Text { get; set; }
}
This code uses javascript and jQuery to get your controls, JSON to serialize the data and save it in a asp hiddenfield then grab the data server-side and deserialize into objects that your code can use. Then take the data and do whatever you need to.
Basically, i want my object back...
I have an Email object.
public class Email{
public string emailAddress;
public bool primary;
public int contactPoint;
public int databasePrimaryKey;
public Email(){}
}
In my usercontrol, i a list of Email objects.
public List<Email> EmailCollection;
And i'm binding this to a GridView inside my usercontrol.
if(this.EmailCollection.Count > 0){
this.GridView1.DataSource = EmailCollection;
this.GridView1.DataBind();
}
It would be really awesome, if i could get an Email object back out of the GridView later.
How do i do this?
I'm also binding only some of the Email object's properties to the GridView as well and they're put into Item Templates.
<Columns>
<asp:TemplateField HeaderText="Email Address">
<ItemTemplate>
<asp:TextBox ID="TextBox1" runat="server" Text=<%# Eval("EmailAddress") %> Width=250px />
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Primary">
<ItemTemplate>
<asp:CheckBox runat="server" Checked=<%# Eval("PrimaryEmail") %> />
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Contact Point">
<ItemTemplate>
<CRM:QualDropDown runat="server" Type=ContactPoint InitialValue=<%# Eval("ContactPoint") %> />
</ItemTemplate>
</asp:TemplateField>
</Columns>
Can GridView even do this? Do i need to roll my own thing? It'd be really cool if it would do it for me.
To elaborate more.
I am saving the List collection into the viewstate.
What I'm eventually trying to get to, is there will be a Save button somewhere in the control, which when the event fires I'd like to create an Email object from a datarow in the GridView which to compare to my original List collection. Then if there's a change, then I'd update that row in the database. I was thinking that if I could put a List collection into a GridView, then perhaps I could get it right back out.
Perhaps I create a new constructor for my Email object which takes a DataRow? But then there's a lot of complexities that goes into that...
ASP.NET Databinding is a one-way operation in terms of object manipulation. However, the DataSource property will contain a reference to your EmailCollection throughout the response:
EmailCollection col = (EmailCollection)this.GridView1.DataSource;
But I have a feeling that what you really want is a control that manipulates your EmailCollection based on user input and retrieve it in the next request. Not even webforms can fake that kind of statefulness out of the box.
Well I ended up looping through my List EmailCollection, which was saved into the ViewState.
So in the page, a Save button is clicked, when the event is caught, I loop through my List Collection and grab the row from the GridView by index.
On the GridViewRow I have to use a GridView1.Rows[i].Cells[j].FindControl("myControl1") then get the appropriate value from it, be it a check box, text box, or drop down list.
I do see that a GridViewRow object has a DataItem property, which contains my Email object, but it's only available during the RowBound phase.
Unfortunately If/When i need to expand upon this Email Collection later, by adding or removing columns, it'll take a few steps.
protected void SaveButton_OnClick(object sender, EventArgs e){
for (int i = 0; i < this.EmailCollection.Count; i++)
{
Email email = this.EmailCollection[i];
GridViewRow row = this.GridView1.Rows[i];
string gv_emailAddress = ((TextBox)row.Cells[0].FindControl("EmailAddress")).Text;
if (email.EmailAddress != gv_emailAddress)
{
email.EmailAddress = gv_emailAddress;
email.Updated = true;
}
...
}
}
I'd still be open to more efficient solutions.
Just a thought, basically a roll your own but not that tricky to do:
Store the list that you use as a datasource in the viewstate or session, and have a hidden field in the gridview be the index or a key to the object that matches the row.
In other words, each row in the gridview "knows" which email object in the list that it is based on.
If you want to hold onto an object like this its easiest to use the viewstate, although you will be duplicating the data but for a small object it should be ok.
ViewState.Add("EmailObj", Email);
EMail email = (Email)ViewState["EmailObj"];