Re: ArrayList Problem - C# Discussion Boards

Have you tried something like

Label1.text = MonthCalender.ToString();

yes , but it doesn't work . I want When i click a day in monthcalendar control ,its value show into the Lable1.
Lable1.Text=MonthCalender1....?
thanks

-- modified at 4:34 Tuesday 7th March, 2006

Handle the calendar's onchanged event and inside that update the label.

Hi all,

i am using Arraylist to store some values
i add the values using the list.Add() method

but when i try to access the values from the list
it gives me exception saying that

object Reference not set to an instance of an object

i try to retrieve the value in the following form

string ss = urls[x].ToString();

i have even tried
string ss = (string) urls[x];

Can anyone help me out of this?

Thanks,

Pramod

This error means one of two things. Either:

You have not initilized the ArrayList

or

You are trying to access an element of the list that does not exist (the index is less than 0 or greater than the number of elements in the list minus one)

sorry that's not the case
i have initialized the Arraylist
also this exceptions comes sometimes
Actually it is in a thread and the values are retrieved for
the first 2 threads but when some thread tries to access the exception occurs
i have even checked the index, it is within the bounds and the values exist

the values are displayed in the watch window

don't actually know wht's happening?

Thanks,

Pramod

Could you post some of the code so I can try and find where you are going wrong?

public void PostPageURLS()
{
string strPostURL="";
string strPostId = "";

bool BreakFlag = false;

//
j=Convert.ToInt32(Thread.CurrentThread.Name);

for(int k=0; k<urls[j].count; k++)
="" {="" {
="" monitor.enter(thread.currentthread);
="" try
="" if(thread.currentthread="" !="null)
" j="Convert.ToInt32(Thread.CurrentThread.Name);
" }
="" catch(exception="" exc)
="" messagebox.show(exc.message);
=""
="" if(k<="" urls[j].count="" &&="" bi="" <="" blogurls.count)
="" string="" keyword="urls[j][k].ToString();
" int="" chpos="keyword.LastIndexOf("=");
" posttext="SearchKeywordsYahoo(keyword.ToString());
" +="SearchKeywordsMSN(keyword.ToString());
" bloglib.movabletypeinterface="" mti="new" webbloggenerator.bloglib.movabletypeinterface(posturls[bi].tostring());

="" object[]="" obj1="{objDT.Rows[(int)" checkedobj[j]].itemarray[0],objdt.rows[(int)="" checkedobj[j]].itemarray[1],objdt.rows[(int)="" checkedobj[j]].itemarray[2],
="" objdt.rows[(int)="" checkedobj[j]].itemarray[3],objdt.rows[(int)="" checkedobj[j]].itemarray[4],k*100="" urls[j].count,
="" "blogging"};
="" checkedobj[j]].itemarray="obj1;
" objdt.acceptchanges();

="" sss="(string)" posturls[bi];="" <-="" occurs="" exception
="" if(sss.indexof("msn")="" post(blogusername[bi].tostring(),blogpassword[bi].tostring(),posttext,urls[j][k].tostring());
="" excc)
="" bi++;
="" }

="" strpostid="mti.NewPost("",BlogUsername[bi].ToString(),BlogPassword[bi].ToString(),"New" post="" "="" +"="" !!!","<a="" href="+urls[j][k].ToString()+">"+urls[j][k].ToString()+"
"+PostText,DateTime.Now,false);

if(Convert.ToInt32(mti.PublishPost(strPostId,BlogUsername[bi].ToString(),BlogPassword[bi].ToString()))>0)
{

// MessageBox.Show("Post Successful !!! "+str+ " " + th.Name);

}
else
{
// MessageBox.Show("Unsuccessful ???");
}

if(strPostId!=null ||strPostId!="")
{
WebBlogGenerator.BLL.PageUrl objPageUrl = new WebBlogGenerator.BLL.PageUrl();
int intPageUrlId=objPageUrl.UpdatePageURL(Convert.ToInt32(PageURLId[j][k]),Convert.ToInt32(BlogURLId[bi]),0);
}

bi++;
if(bi == BlogURLS.Count)
bi=0;
Monitor.Exit(Thread.CurrentThread);
Thread.Sleep(5000);
}
}

}

hope u understand that....

Thanks,
Pramod

hi all,
Actually i am a beginner in visual studio c# development and developing a software for our firm in c# (windows forms).
The main task of mine is to display the contents of the floppy when i click on the button in the windows forms and display the contents in the another window forms.Can anybody help me and guide me to go about it?

Nitin_ap

what do you mean with the word "content" ? is content Files list in Floppy Disk ? You can easily get files content of your floppy disk by using System.IO.Directory.GetFiles . You can get your Floppy Disk drive info by using System.Environment.GetLogicalDrives

good luck !

Is there a way to rename the hostname using C#?

thanX in advanced

Why do you want to do that programmatically? There are a lot of things to be taken care of like Administrator credentials, Domain Authentication etc.

Vasudevan Deepak Kumar
Personal Web: http://www.lavanyadeepak.tk/
I Blog At:
http://www.dotnetjunkies.com/weblog/deepak/
http://deepakvasudevan.blogspot.com/
http://deepak.blogdrive.com/

The application that I have written perfroms additional tasks (editing INI, environment variables, XML) the only thing that I need to do is rename the hostname at this time.

I just started playing around with the Mdi Containers. I have one parent and four children that i open inside this parent form. what i want to do is check if a child form is already open inside of this parent, and if so it must be closed first, as to try and avoid the user from opening multiple child forms of the same child, if that makes any sense.

I've tried the Parent.hasChildren()
but that returns true no matter whether a child window is open or not.

Any help will be appreciated

Thanx in advance

Do something like this:

private void newWindowType1ToolStripMenuItem_Click(object sender, EventArgs e)
{
   if (!ContainsChildForm(typeof(child1)))
   {
       child1 c = new child1();
       c.MdiParent = this;
       c.Show();
   }
}

private void newWindowType2ToolStripMenuItem_Click(object sender, EventArgs e)
{
   if (!ContainsChildForm(typeof(child2)))
   {
       child2 c = new child2();
       c.MdiParent = this;
       c.Show();
   }
}

private bool ContainsChildForm(Type t)
{
   for (int i = 0; i < this.MdiChildren.Length; i++)
   {
       if (t.IsInstanceOfType(this.MdiChildren[i]))
       {
           return true;
       }
   }
   return false;
}

DigitalKing wrote:
if (!ContainsChildForm(typeof(child1)))

Does not reconize ContainsChildForm

I posted the code for this function before, but here it is again:

private bool ContainsChildForm(Type t)
{
   for (int i = 0; i < this.MdiChildren.Length; i++)
   {
       if (t.IsInstanceOfType(this.MdiChildren[i]))
       {
           return true;
       }
   }
   return false;
}

That worked 100, but how do I get the focus back to that childform if it exists?

private void CreateUniqueChild(Type t)
{
   int index = GetChildIndex(t);
   if (index == -1)
   {
       Form f = (Form)Activator.CreateInstance(t);
       f.MdiParent = this;
       f.Show();
   }
   else
   {
       this.MdiChildren[index].Focus();
   }
}

private int GetChildIndex(Type t)
{
   for (int i = 0; i < this.MdiChildren.Length; i++)
   {
       if (t.IsInstanceOfType(this.MdiChildren[i]))
       {
           return i;
       }
   }
   return -1;
}

private void newWindowType1ToolStripMenuItem_Click(object sender, EventArgs e)
{
   CreateUniqueChild(typeof(child1));
}

private void newWindowType2ToolStripMenuItem_Click(object sender, EventArgs e)
{
   CreateUniqueChild(typeof(child2));
}

private void newWindowType2ToolStripMenuItem_Click(object sender, EventArgs e)<br />
{<br />
   if (!ContainsChildForm(typeof(child2)))<br />
   {<br />
       child2 c = new child2();<br />
       c.MdiParent = this;<br />
       c.Show();<br />
   }<br />
   else<br />
       c.Activate();<br />
}<br />
<br />
private bool ContainsChildForm(Type t)<br />
{<br />
   for (int i = 0; i < this.MdiChildren.Length; i++)<br />
   {<br />
       if (t.IsInstanceOfType(this.MdiChildren[i]))<br />
       {<br />
           return true;<br />
       }<br />
   }<br />
   return false;<br />
}

thanx a mil, works like a bomb

after o add new column inside the datatable and bind into datagrid

DataColumn dc = new DataColumn();
DataTable dt = new DataTable();

dc.AutoIncrement = true;
dc.AutoIncrementSeed =1;
dc.Unique = true;
dc.ColumnName = "No";
dt.Columns.Add(dc);

SqlConnection objCN = new SqlConnection();
SqlCommand objCMD = new SqlCommand();
SqlDataAdapter objDA = new SqlDataAdapte();

objCN.ConnectionString = ConfigurationSettings.AppSettings["DSN"];
objCMD.Connection = objCN;
objCMD.CommandText = cmdText;
objCMD.CommandTimeout = 30;
objDA.SelectCommand = objCMD;

objCN.Open();
objDA.Fill(dt);
objCN.Close();

dGridRecord.DataSource = dt;
dGridRecord.DataBind();

but the new column 'No' i add in is not appear the increment number in my page after i run it.
wat value i need set data field for tis new column 'No' seem tis is auto generate number and no inside my database.

how i bind the 'No' column in my datagrid?? D'Oh! | :doh:

angela

Hi
i think you have done well but you have missed to set autoincrement step in yours code. so add the following line of code just after the line where you have set the autoincrementseed.

dc.AutoIncrementStep = 1;

i htink yours problem will be solved. Smile | :)

just now i set autoincrementseed,

dc.AutoIncrementStep = 1;

but the column 'No' also display nothing.....
i guess is my datagrid problem where i add a 'No'bound column but i not set d data field inside tat column... coz i dun know wat attribute to put in seem it no exit in my database, this column is auto generate number...

i also no sure whether i had bind the datatable to my datagrid correctly or not?? Confused | :confused:

angela

have you made autogenerated column property of datagrid false? if you are using all the columns of datasource in datagrid then make it true. in that case you will not need to specify the column name for datagrid. Smile | :)