Re: NULL problem - C# Discussion Boards

30-Aug-07 19:45

hi there,
i have a problem that how can check the value of datagridview is null ??

if i write

if (DataGridView1[5, a].Value.ToString() == null)

if (DataGridView1[5, a].Value.ToString().Contains (null))

if (DataGridView1[5, a].Value.Equals(null))

all gives the same error
Object reference not set to an instance of an object.

for temporary i did

string aaa = DataGridView1[5, a].Value + "D";
                    if (aaa.Trim )== "D")

its working but i dont like this way

some know any other good and short way ??

Becoming Programmer...

Martin#30-Aug-07 20:01

Martin#

30-Aug-07 20:01

Hello,

Have you tried:
if (DataGridView1[5, a].Value != null)
{
//Go on
}

All the best,

Martin

Xmen Real 30-Aug-07 22:53

30-Aug-07 22:53

damn..!! why i dont think it before anyway thank you guys below and above this post

Becoming Programmer...

V.30-Aug-07 20:31

30-Aug-07 20:31

Did you try this?

DataGridView1[5, a].Value == DBNull.Value

V.
If I don't see you in this world, I'll see you in the next one... And don't be late. (Jimi Hendrix)

girm30-Aug-07 20:39

girm

30-Aug-07 20:39

Hi,

According to the exception it is quite clear that CLR bumped into a null value while evaluating
"DataGridView1[5, a].Value"

what means "DataGridView1[5, a].Value.toString()" if "DataGridView1[5, a].Value" is null ??

You might not assume DataGridView1!=null nor a!=null nor DataGridView1[5, a].Value!=null
though the following test should solve your problem :

if (DataGridView1[5, a]==null or DataGridView1[5, a].Value==null)
{
///
}

Hope it helps

Vasudevan Deepak Kumar30-Aug-07 22:18

Vasudevan Deepak Kumar

30-Aug-07 22:18

if (DataGridView1[5, a] == null)

Vasudevan Deepak Kumar
Personal Homepage
Tech Gossips

Martin#30-Aug-07 22:22

Martin#

30-Aug-07 22:22

Hello,

Vasudevan Deepak Kumar wrote:
if (DataGridView1[5, a] == null)

I guess this will not help,
if this is true:
for temporary i did

string aaa = DataGridView1[5, a].Value + "D"; if (aaa.Trim )== "D")

its working but i dont like this way

All the best,

Martin

Syed Mujtaba Hassan31-Aug-07 1:00

Syed Mujtaba Hassan

31-Aug-07 1:00

I think your grid must be having only 5 records from 0 to 4.
So its not geting the 6th record.

Mujtaba

"If both of us are having one apple each and we exchange it, at the end we both will have one apple each. BUT if both of us are having one idea each and we exchange it, at the end both of us will be having two ideas each."

Xmen Real 31-Aug-07 2:19

DLL output file naming convension

31-Aug-07 2:19

no buddy you misundertood the question that wasnt the problem, and now problem has been solved...;););)

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George_George30-Aug-07 19:44

George_George

30-Aug-07 19:44

Hello everyone,

Previously, I think if I am using namespace ns1, and declaring and defining a public class cs1 using C# Class Library project, I have to name the output DLL name to be ns1.dll. I have this idea because I noticed that Microsoft names the DLLs, like System.dll for name space System, System.Data.dll for name space System.Data.

Now I tried that I can name the output DLL name to arbitrary name (not ns1), like mylib.dll. Then the applications which use the DLL still work.

So, I think the conclusion should be, we can use arbitrary name which is not related to namespace. Right?

thanks in advance,
George

\laddie30-Aug-07 20:55

\laddie

30-Aug-07 20:55

I assume the name of the assembly does't matter as long as you added your assembly to your project and the contents in the assembly is not changed.

George_George30-Aug-07 21:23

George_George

30-Aug-07 21:23

Thanks zion417,

I think you are also not following the naming convension which Microsoft does (e.g. namespace.dll). Right? Smile | :)

regards,
George

\laddie30-Aug-07 21:34

\laddie

30-Aug-07 21:34

It depends on my project.Normally we follow the same convension .Root.Child1.. etc. I was just saying the name of the "assembly" done actually matter.

how to use Contains method??

George_George30-Aug-07 21:49

George_George

30-Aug-07 21:49

Thanks zion417!

regards,
George

Situ1430-Aug-07 18:46

Situ14

30-Aug-07 18:46

how to use contains method

I want to search more than one string like this
line.Contains("AssemblyVersion","AssemblyCompany","AssemblyProduct","AssemblyCopyright","AssemblyTrademark","AssemblyCulture")

how could i search??

plz reply if anybody knows
Thanks

Re: how to use Contains method?? [modified]

Martin#30-Aug-07 19:26

Martin#

30-Aug-07 19:26

Hello,

Other then Regex,
what you need is not implemented in the framework string class, AFAIK. (At least not in .Net 1.1)

The string class provides the IndexOfAny method, which only is able the search for chars.

But you could use a self written method!
Like this:
This method returns the startindex of the string which is found first.

public static int IndexOfAnyString(string TextToParse, string[] TextsToSearch)
{
	int index=-1;
	if(TextsToSearch!=null)
	{
		foreach(string actSearchText in TextsToSearch)
		{
			//Searchtext not null and not empty string
			if(actSearchText!=null && !actSearchText.Equals(string.Empty))
			{
				//call the string.IndexOf method
				index = TextToParse.IndexOf(actSearchText);
				if(index>=0)
				{
					//found a string;
					break;
				}
			}
		}
        }
	return index;
}

In .Net > 1.1, you could use the "Contains" method instead of "IndexOf"!

Call it like this:

string mainline = "Hello codeproject world";
int index = IndexOfAnyString(mainline, new string[] {"msdn", "codeproject ", "blablabla"});
//Will return: 6

This is just a basic implementation of the problem.

You could add some more features like:
case sensitivity (true/false)
out param string, which returns the matching string
returning an array of int index values for all search texts
.
.
.

Hope it helps!

-- modified at 1:43 Friday 31st August, 2007

All the best,

Martin

Re: how to use Contains method?? [modified]

Situ1430-Aug-07 20:01

Situ14

30-Aug-07 20:01

Thanks For reply..

I'm using like this

if (line.Contains("AssemblyVersion")||line.Contains("AssemblyCompany")||line.Contains("AssemblyProduct")||line.Contains("AssemblyCopyright")||line.Contains("AssemblyTrademark")||line.Contains("AssemblyCulture"))
{
line = string.Concat("// ", line ," // comment");

}

its working..
But its adding comment withount indenting means..

AssemblyProduct //comment
AssemblyProduct //comment
AssemblyProduct //comment

but i want indentation like this

AssemblyProduct //comment
AssemblyProduct //comment
AssemblyProduct //comment

how i make indentation...
if you know then plz reply..

Thanks in advance

-- modified at 3:16 Friday 31st August, 2007

Re: how to use Contains method??

Xmen Real 30-Aug-07 19:37