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my dataTable has columns ID and Name
in my datagrid i have hidden Column Id and only display Column Name
code in C#
table.Columns["Id"].ColumnMapping =MappingType.Hidden;
datagrid.DataSource =table;
how can i access my Column id
i have tried
DataTable tb =(DataTable)DataGrid.DataSource;
DataRow row =dt.Rows[0];
decimal id =(decimal)row[1].ToString();
olny get errors
thanks
regards paula
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This is because row[1].ToString(); return a string which cannot be cast to decimal. If the column is of type decimal then try decimal id =(decimal)row[1]; or even better (as it works with any numerical values) decimal id =Convert.ToDecimal(row[1]);
And in future please post the error message you get (and exactly where it occurs).
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I have Header User control (which contains ASP DropDownList with AutoPostBack Property True) and WebForm1.aspx page in my application. Header1.ascx user control embedded with WebForm1.aspx page. Now if I choose the items in DropDownList which is in Header1.ascx the WebForm1.aspx page load event fires first and then the Header1.ascx Page load event fires. But I am assigning session value in Header1.ascx page. So all I want is the header1.ascx page load should fire first then the webform1 page load event or else the before the webform1 page load event get fires I want to assign the value to the session. How do I resolve this?
In Header1.ascx page load event I have write the following:
If (IspostBack)
//assigning session value
DropDownList1_SelectedIndexChanged event
//assigning session value
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Hi Karthi,
Change private to public (private void Page_Load(object sender, System.EventArgs e) to public void Page_Load(object sender, System.EventArgs e)). On webpage page_load event create an instance for your control(webusercontrol1 wc = new webusercontrol1()) and we can fire the usercontrol page_load event by using the instance variable (wc.Page_load(sender, e)). Let me know your comments if you have any queries in this code.
Thanks
Warm Regards
Prakash-B
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I'm working on WSe 2.0 and while calling some function say CreateApplication, I'm receiving following error.
System.Exception was unhandled
Message="WSE104: An asynchronous callback raised an exception."
Source="Microsoft.Web.Services2"
StackTrace:
at Microsoft.Web.Services2.AsyncResult.RaiseUnhandledException(Object
o)
at
System.Threading._ThreadPoolWaitCallback.WaitCallback_Context(Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext
executionContext, ContextCallback callback, Object state)
at
System.Threading._ThreadPoolWaitCallback.PerformWaitCallback(Object state)
Inner exception says:
"Could not find any resources appropriate for the specified culture or the neutral culture. Make sure \"Microsoft.Csf.SDK.Microsoft.Csf.SDK.resources\" was correctly embedded or linked into assembly \"Microsoft.Csf.Sdk\" at compile time, or that all the satellite assemblies required are loadable and fully signed."}
I'm using win 2k3 server with SP1 installed and .NET 2.0 to call the method. Do anybody have any idea what could be the possible reason. I've done lot of search on net and applied all solutions like increasing execution time and other time spans. But I'm still facing the same error. Also the error occurs only when I call the function from other machine. On the same machine if i execute the same code it works without any error. Can anybody help me out in this case?
Really there is no material available on net.
Regards
Jayant D. Kulkarni
Brainbench Certified Software Engineer in C#, ASP.NET, .NET Framework and ADO.NET
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i have project about image processing. I have most of them but at the end i will show two images. One of the image is 5 mbyte jpeg and i dont want to refresh it, and other image contains only lines about the first images. i search most the image processing project.
At the end i will explain from another sight. I will use two image box layer. One of them shows the image which has very big file size. And other image box works as transparent image box. This image box contains only lines, and i will refresh it very frequently.
I try different approach to this problem but it always flickiring because of the image size is very big when it is opened in the ram area.
Is there anybody help me :    ;P;)  
thanks
-- modified at 9:32 Friday 13th January, 2006
the question is, how can i create a transparent image box ?
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Out of sheer curiosity I have a quick question relating to C# performance. I have the two following methods:
public static string VerboseProgrammingMethod()
{
System.Guid g = Guid.NewGuid();
string s = g.ToString();
string f = s.Substring(0,4);
return f;
}
public static string OneLineProgrammingMethod()
{
return Guid.NewGuid().ToString().Substring(0, 4);
}
As you can see both of them will generate exactly the same output as they essentially perform the same functions. The question is is one of them quicker/less memory intensive than the other?
I am under the impression that it doesnt make any difference whatsoever, but I would be grateful if somebody could confirm this
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run an app called ildasm from the VSNet command prompt and open your assembly with both methods in.
You should see that the generated IL is exactly the same.
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The first methods creates two strings(s,f) and it should be more memory consuming.
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I'm afraid that's not true, since the resulting IL is identical.
Regards,
mav
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The two strings are created in both codes. The only difference is that the references to the strings are declared as variables in one code, while in the other code the compiler will create the references itself to handle the strings.
---
b { font-weight: normal; }
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Like the others say, both are the same. #1 is must easier to debug though, and should allways be used (for clarity too). Make a habit of it. We are proffesionals, not script kiddie/wannabe hackers
NOTE: That saying, I still take the 'short' route sometimes 
xacc.ide-0.1.1.4 - now with LSharp integration and scripting :)
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I totally agree with your professionals vs script kiddie comment, but on occasion it is sometimes necessary to make sacrifices for performance.
As suggested by Jamie4C I created the following class library and ran it through ILDasm
public class Class1
{
public static string VerboseProgrammingMethod()
{
System.Guid g = Guid.NewGuid();
string s = g.ToString();
string f = s.Substring(0,4);
return f;
}
public static string OneLineProgrammingMethod()
{
return Guid.NewGuid().ToString().Substring(0, 4);
}
}
}
Now in theory the IL code for these two functions should be exactly the same, interestingly there are differences. I am no IL expert so this might be a red herring, but here is the IL code:
.method public hidebysig static string VerboseProgrammingMethod() cil managed
{
.maxstack 3
.locals init ([0] valuetype [mscorlib]System.Guid g,
[1] string s,
[2] string f,
[3] string CS$00000003$00000000)
IL_0000: call valuetype [mscorlib]System.Guid [mscorlib]System.Guid::NewGuid()
IL_0005: stloc.0
IL_0006: ldloca.s g
IL_0008: call instance string [mscorlib]System.Guid::ToString()
IL_000d: stloc.1
IL_000e: ldloc.1
IL_000f: ldc.i4.0
IL_0010: ldc.i4.4
IL_0011: callvirt instance string [mscorlib]System.String::Substring(int32,
int32)
IL_0016: stloc.2
IL_0017: ldloc.2
IL_0018: stloc.3
IL_0019: br.s IL_001b
IL_001b: ldloc.3
IL_001c: ret
}
.method public hidebysig static string OneLineProgrammingMethod() cil managed
{
.maxstack 3
.locals init ([0] string CS$00000003$00000000,
[1] valuetype [mscorlib]System.Guid CS$00000002$00000001)
IL_0000: call valuetype [mscorlib]System.Guid [mscorlib]System.Guid::NewGuid()
IL_0005: stloc.1
IL_0006: ldloca.s CS$00000002$00000001
IL_0008: call instance string [mscorlib]System.Guid::ToString()
IL_000d: ldc.i4.0
IL_000e: ldc.i4.4
IL_000f: callvirt instance string [mscorlib]System.String::Substring(int32,
int32)
IL_0014: stloc.0
IL_0015: br.s IL_0017
IL_0017: ldloc.0
IL_0018: ret
}
-- modified at 7:02 Monday 9th January, 2006
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Is this the debug or the release build? There shouldn't be any differences in the release build. The debug build will contain some differences which is why the first version of the code is easier to debug (the compiler doesn't perform so many optimisations in debug builds)
ColinMackay.net
"Man who stand on hill with mouth open will wait long time for roast duck to drop in." -- Confucius
"If a man empties his purse into his head, no man can take it away from him, for an investment in knowledge pays the best interest." -- Joseph E. O'Donnell
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The above IL listings were from a debug build, but there are still differences in a release build:
.method public hidebysig static string VerboseProgrammingMethod() cil managed
{
.maxstack 3
.locals init (valuetype [mscorlib]System.Guid V_0,
string V_1,
string V_2)
IL_0000: call valuetype [mscorlib]System.Guid [mscorlib]System.Guid::NewGuid()
IL_0005: stloc.0
IL_0006: ldloca.s V_0
IL_0008: call instance string [mscorlib]System.Guid::ToString()
IL_000d: stloc.1
IL_000e: ldloc.1
IL_000f: ldc.i4.0
IL_0010: ldc.i4.4
IL_0011: callvirt instance string [mscorlib]System.String::Substring(int32,
int32)
IL_0016: stloc.2
IL_0017: ldloc.2
IL_0018: ret
}
.method public hidebysig static string OneLineProgrammingMethod() cil managed
{
.maxstack 3
.locals init (valuetype [mscorlib]System.Guid V_0)
IL_0000: call valuetype [mscorlib]System.Guid [mscorlib]System.Guid::NewGuid()
IL_0005: stloc.0
IL_0006: ldloca.s V_0
IL_0008: call instance string [mscorlib]System.Guid::ToString()
IL_000d: ldc.i4.0
IL_000e: ldc.i4.4
IL_000f: callvirt instance string [mscorlib]System.String::Substring(int32,
int32)
IL_0014: ret
}
-- modified at 7:31 Monday 9th January, 2006
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After a lot of pain I managed to get the Windows Debugger hooked up to a process containing these two methods (using the MethodImpl attribute to suppress inlining), and dump the JITted code. Here's the result:
OneLineProgrammingMethod:
sub esp,0x10
xor eax,eax
mov [esp],eax
mov [esp+0x4],eax
mov [esp+0x8],eax
mov [esp+0xc],eax
lea ecx,[esp]
call mscorlib_79990000+0x35d28 (799c5d28)
push 0x0
lea ecx,[esp+0x4]
mov edx,[01c415d0]
call mscorlib_79990000+0x35de0 (799c5de0)
push 0x4
mov ecx,eax
xor edx,edx
cmp [ecx],ecx
call mscorlib_79990000+0x6b20 (79996b20)
add esp,0x10
ret VerboseProgrammingMethod:
sub esp,0x10
xor eax,eax
mov [esp],eax
mov [esp+0x4],eax
mov [esp+0x8],eax
mov [esp+0xc],eax
lea ecx,[esp]
call dword ptr [mscorlib_79990000+0x234a08 (79bc4a08)]
push 0x0
lea ecx,[esp+0x4]
mov edx,[01c415d0]
call dword ptr [mscorlib_79990000+0x234a28 (79bc4a28)]
push 0x4
mov ecx,eax
xor edx,edx
cmp [ecx],ecx
call mscorlib_79990000+0x6b20 (79996b20)
add esp,0x10
ret The only difference is that for some reason the JIT compiler has decided to call through a table for the verbose method - the functions called are exactly the same.
I'm actually surprised - I was expecting the IL to be different since the C# compiler does very little optimisation but I wasn't expecting a difference in the JITted code.
Nevertheless you should normally forget about micro-optimisations like this and concentrate on the areas that will have the biggest impact.
Stability. What an interesting concept. -- Chris Maunder
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Mike Dimmick wrote: Nevertheless you should normally forget about micro-optimisations like this and concentrate on the areas that will have the biggest impact.
In this example, I agree it is an "optimisation" that will save nano seconds if that.
That being said, if the methods were dealing with much larger objects it could potentially be something worth considering.
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As the only difference in coding is to keep references to the objects created, it doesn't matter how large the objects are. The size of a reference is always the same.
When optimizing code it's very useful to know what the code really does, in order to find out what code is worth optimizing, and how.
Example:
int a = 42;
string y = a + "," + a;
That looks simple, but can be written much more efficient in this more lengthy way:
int a = 42;
string x = a.ToString();
string y = x + "," + x;
The first code will be executed something like:
int a = 42;
string y = string.Concat(Number.FormatInt32((int)new Object(a), null, NumberFormatInfo.GetInstance(null)), (string)(object)",", Number.FormatInt32((int)new Object(a), null, NumberFormatInfo.GetInstance(null)));
while the second code will be executed as:
int a = 42;
string x = Number.FormatInt32(a, null, NumberFormatInfo.GetInstance(null));
string y = string.Concat(x, ",", x);
---
b { font-weight: normal; }
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The latter seems to be faster, is this correct?
modified 12-Sep-18 21:01pm.
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Probably a half second faster over the span of 1 million calls to it. But, of course, your milage may vary depending on your machine and how you drive it.
RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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hi,
a very simple question:
when i create an windows application in VS the starting point is usually the form.
i would like my base class as a starting point (having the MAIN method) from which i start the gui. how do i do it?
when i simply do:
MyGUI gui = new MyGUI();
gui.Show();
the gui does not show for long.
regards,
rnv
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Application.Run(new MyGUI()) should be enough
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If MyGUI is a form then try with Application.Run(new MyGUI());
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Hi everybody! I'm buliding a little Database where I have to insert Data through a mask made with some TextBox form and TextLable form.
Can I bind a dataset to this kind of forms? How can I make possible to show in the boxes the selected row of the dataset?
Do the Framework implements this functionality?
Thank you!
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