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I am new to web programming but have extensive experience with desktop apps. I have a question about asp.net. If I have two radio buttons called yes and no. If user checks no then I want a dropdownlist to become visible else invisible.
Now the questions I have are:
1. I created an event handler for the radio buttons which make the list visible and invisible. But if the AutoPostBack property is set to false then the event handler will only be invoked when a postback occurs (even by some other control), correct?
2. How can I make the list invisible and visible if postback is false? See if the AutoPostBack property of the radio button is false then its event handler is not fired upon check change. I want to make the list visible right away when the check changes.
3. What should I be aware of if AutoPostBack property is set to true? Any disadvantages or advantages?
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1 - correct.
2 - the way you should do this is by using javascript, no need to do a postback just to make a control visible.
3 - a page that posts back all the time is a PITA, especially when people are used to AJAX.
Christian Graus
Driven to the arms of OSX by Vista.
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Wrap the dropdown in a div tag, add a javascript function in the head of your page to alter the visibility of this div, and call it via onclick attributes added to your radio buttons in code-behind:
HTML:
<asp:RadioButton id="radYes" Runat="server" Text="Yes" GroupName="radYN"></asp:RadioButton>
<asp:RadioButton id="radNo" Runat="server" Text="No" GroupName="radYN"></asp:RadioButton>
<div id="divDD" style="display:none;"> <!-- delete this style if default is visible -->
<asp:Dropdownlist runat="server" id="ddlNo">
</asp:DropdownList>
</div>
JavaScript:
function toggle() {
if (document.getElementById("radYes").checked) {
document.getElementById("divDD").style.display = 'none';
} else {
document.getElementById("divDD").style.display = 'inline';
}
Code-behind:
radYes.Attributes.Add("onclick", "toggle()")
radNo.Attributes.Add("onclick", "toggle()")
And all achieved without postback - which should be avoided wherever possible as it (obviously enough) increases bandwidth as well as the load on the server.
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why not just add the onclick inline ? Will ASP.NET wipe it for it's own ?
Christian Graus
Driven to the arms of OSX by Vista.
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well.. it's just the "proper" way to do it in Visual Studio!! VS will underline it in red and tell you it's not a valid property - which it isn't of the server control; it's only when the page renders it as an html control that it becomes so.
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Fair enough. I'd tend to do it inline because I'd regard it as cleaner, and not be dictated to by the IDE. but, your way works, no doubt.
Christian Graus
Driven to the arms of OSX by Vista.
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Phil,
Where in the code behind should I add the attribute to the collection? Page_Init()?
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I have a DataSet with two tables with a relationship.
dataSetNodeData.Relations.Add(new DataRelation("Relationship",
dataTableTransmittal.Columns["Node ID"],
dataTableDocuments.Columns["Parent"]));
This is working, but now the customer have changed the indata so Parent is now a commaseparated string with id numbers so the same document can belong to several Node ID's.
Can I make the DataRelation work with a commaseparated string? Or do I have to rewrite my application totaly?
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No, that's not going to work. You need to rethink your architecture. I suspect you need to change your dataTableDocuments to have a record per parent id, even if they are stored as a csv. I'd say don't store them that way in the first place, just add records for each parent relationship.
Christian Graus
Driven to the arms of OSX by Vista.
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Yes, that's the way I thought that I hade to go.
I can't affect the indata as it is a export (xml) from a CMS system.
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I have 5 radiobuttons. When i select one, it should be made bold. Other radiobuttons should be displayed with normal font. How to achieve this?
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javascript. Handle the event and then use JS to bold the text. The text is in a label, it's actually not part of the radio button in HTML, so there's some hoops you'll need to jump through.
Christian Graus
Driven to the arms of OSX by Vista.
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here is my code :
row["ReductionDetails"] = row["ReductionDetails"] + "" + Value
+ "% of " + GetProductNameById(ProductId) + '\n';
what i want to get :
< td >
MY FIRST LINE
MY SECOND LINE
< /td >
there is no result with : '\n' and what i got : MY FIRST LINEMY SECOND LINE
i tried the "< br / >" and what i got : MY FIRST LINE < br / >MY SECOND LINE
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\n is a waste of time in a website. If the br tag is shown then it's being escaped.
Christian Graus
Driven to the arms of OSX by Vista.
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How I can upload doc files in ASP.Net and later retieve it using Gridview control.please specify complete code along with necessary table to be built in SQL Server 2005 Express Edition
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shreesh_9 wrote: please specify complete code along with necessary table to be built in SQL Server 2005 Express Edition
Dream on, buddy, we're not here to do your work for you.
If you don't want to display the contents of the doc file, it's pretty trivial. You use an upload control, which is the only way to upload a file, then you store it as a blob with an id in the database. Then you make your download URL pass the id, get the blob from the DB and send it to the user.
Christian Graus
Driven to the arms of OSX by Vista.
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Hi, I am getting the following error by reading the data from CSV file to dataset.
"'C:\Documents and Settings\satish.gorijala\Desktop\csvData.csv' is not a valid path. Make sure that the path name is spelled correctly and that you are connected to the server on which the file resides"
string _filepath = @"C:\Documents and Settings\satish.gorijala\Desktop\csvData.csv";
string _fileexten = Path.GetExtension(_filepath);
string strConn = "";
if (_fileexten == ".csv")
{
strConn = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + _filepath + ";Extended Properties='text;HDR=Yes';";
}
OleDbConnection oledbconn = new OleDbConnection(strConn);
oledbconn.Close();
oledbconn.Open();
OleDbDataAdapter myCommand = new OleDbDataAdapter("SELECT * FROM [Sheet1$]", oledbconn);
DataSet myDataSet = new DataSet();
myCommand.Fill(myDataSet, "ExcelInfo");
dt = myDataSet.Tables[0];
oledbconn.Close();
myCommand.Dispose();
G. Satish
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Satish - Developer wrote:
"'C:\Documents and Settings\satish.gorijala\Desktop\csvData.csv' is not a valid path
This is just a guess, and don't quote me or anything, but at a push i'd hazard a guess that it could possibly be that the path specified does not exist.
Once again, just a guess and all. 
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i show my files in gridview, and i have a column that is checkbox and i can select multiple file. i want with select multiple checkbox i can send multiple file to print. can i do this? can anybody help me? plz
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The only thing a web app can do, is print the full browser window. So you need to open a print view for any document you want to print. Of course, the browser has to be able to display it.
Christian Graus
Driven to the arms of OSX by Vista.
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Hi all,
Any one suggest me how to edit my url and submit the page on button click with out using Response.redirect.
for eg:
www.mysite.com/default.aspx
this is my page, on button click the page should submit and reload, the url should look like www.mysite.com/default.aspx?step=1 (no response.redirect, because i am losing the viewstate even though i set the EnableViewState="true")
Thank you
Know is Drop, Unknown is Ocean
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If you redirect (for this read reload), you will not get any viewstate, you are reloading the page. Can you not just set a Viewstate-ed variable when you post back in the button click and re-bind your page?
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Hi All,
We are using custom http handler, where we fetch large data value from a text field of database.
We later split this large data into chunks and write to response objects.
We are facing unique problem when the text size is nearly 4mb and when we are trying to write to context.Response.Write. It does not write in a single attempt, but calls the HandleRequest many times trying to write. In this time I am getting internet message Operation aborted.
Can any one tell how to overcome this scenario.
Thanks in Advance,
Naga.
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let there be a gridview with some BoundFields then how i can retrive the
that value of a particular bound field value using javascript
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Basically you need to make sure you give the controls that contain the values, ids that you can use to find those controls in js. A common way is to append the row number to the fields and build the ids row by row
Christian Graus
Driven to the arms of OSX by Vista.
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