Q) What's Wrong in this? Getting "NullReferenceObject Exception"

C#:
I have getting "System.NullReferenceException: Object refernce not set to an instance of an object, at" .
This Exception is getting when giving the some text into the textbox's & Clicking Button of Windows Control Library form (usercontrol) which is placed the UC_submitcontrol usercontrol on the UCTestApp1 Windows Form and Execute.

See the Pictures:



Code for UC_SubmitControl1:

namespace UC_SubmitControl1
{
    public partial class UC_SubmitScreen : UserControl
    {
        public delegate void SubmitClickHandler();
        public event SubmitClickHandler SubmitbtnClicked;

        public UC_SubmitScreen()
        {
            InitializeComponent();
        }

        private void btnSubmit_Click(object sender, EventArgs e)
        {
            if(tbText.Text.Length==0)
                MessageBox.Show("Please Enter Some Text..!");
            else
            {
                OnSubmitClicked();
            }
        }

        protected virtual void OnSubmitClicked()
        {
            if (SubmitbtnClicked != null)
            {
                SubmitbtnClicked();  // Notify Subscribers
            }
        }

        public string Prop_TextHere
        {
            get { return tbText.Text; }
            set { tbText.Text = value;  }
        }
    }
}

See the Picture for UC_TestApp1 [Windows Application]


Code for UC_TestApp1:

namespace UC_TestApp1
{
    public partial class Form1 : Form
    {
        private UC_SubmitControl1.UC_SubmitScreen submitscrObj;
        //private System.ComponentModel.Container components = null;


        public Form1()
        {
            InitializeComponent();
        }

        private void uC_SubmitScreen1_SubmitbtnClicked()
        {
            try
            {
                MessageBox.Show(String.Format("Hello, {0}!", submitscrObj.Prop_TextHere));
                //string aa = submitscrObj.Prop_TextHere;
                //MessageBox.Show("Hello ", +aa.ToString()+" !");
                //this.Close();
            }
            catch (Exception e)
            {
                MessageBox.Show(e.ToString());
                this.Close();
            }
        }        
    }        
}

How do i make MDI Parent & Child Forms in C#.NET as looks like as Master & Child Pages in ASP.NET?

C#:
I have to develop project that looks like "Master & child" Pages in ASP.net, i.e., "MDI-Parent & MDI-child" But here i need not want the titlebar for child form and should not have child form minimizeble (i.e, ChildForm should be fit in the content part of a MDI-Parent form).

Here my idea is, First i have to design a MDI Parent form with companies Logo picture bar & 3 buttons(Rounded Rectangular image buttons) namely "EntryForm" button, "UpdateForm" button, "ViewForm" button. In that if i clicked "EntryForm" button, then the Entryform MDI-child should be should in that MDI-Parent Form and as the same for other two buttons also. Note: Even though the MDI-Child form should works as it as independent form

Note:

At Present i'm using the Custom User controls, But getting confusions in linking the custom user control forms. I have used (designed) 3 custom controls (UC_EntryForm, UC_UpdateForm, UC_ViewForm) as a child form looks. And One Normal Window Form with BackGround Companies Logo picture and a Panel (into which the custom controls will shown) & 3 buttons. For each button has needs a code to load a specific custom user control. How?

How to write code : for every button click, should add the Date data (taking from textbox1) into "Sample" Table which as Date field

C#:In my application program, i have textbox named "Curdate" with my prefferred format. when i click a button1, the data (from the "Curdate" textbox) is add into the "CDate" field of the Table "DateTb".
if the table have not existed, then it should be create a table "DateTb" along with a field "CDate" and add the data (as row-by row)

Note: This the same process for i need to use the ExcelSheet, Ms-Access, SQLsever2005.

How to insert a Line of data in the middle of the Existiong Text File?

class InsertMidLine11
    {
        static string path = "@/../../test1.txt"; //refers to bin folder 
        static string data = "Line5";
        static int lineno = 10;

        static void Main(string[] args)
        {
            InsertIntoFile(path,data,lineno);
        }

        public static void InsertIntoFile(string Path, string Data, int LineNumber)
        {
            StringBuilder result = new StringBuilder();
            FileStream fs = new FileStream(Path, FileMode.Open, FileAccess.ReadWrite);
            int lines = 0;
            using (StreamReader sr = new StreamReader(fs))
            {
                string line;
                while ((line = sr.ReadLine()) != null)
                {
                    if (lines == (LineNumber - 1))
                    {
                        result.Append(Data);
                        result.Append(" | ");
                    }
                    result.Append(line);
                    result.Append(" | ");
                    lines++;
                }
            }
            string fullstr = result.ToString();
            string[] text = fullstr.Split('|');
            using (StreamWriter sw = new StreamWriter(Path))
            {
                for (int i = 0; i < text.Length; i++)
                {
                    string item = text[i].Trim(); 
                    sw.WriteLine(item);
                    Console.WriteLine(item);
                }
            }
        } 
    }

That results:

Some Line1
Some Line2
Some Line3
Some Line4
Some Line5
Some Line6

Here i have to insert a Line "Some Line10" infront of the Line "Some Line5" that Looks as:

Some Line1
Some Line2
Some Line3
Some Line4
Some Line10
Some Line5
Some Line6


Note: first create test1.txt along above data and place this in the current project's bin folder.

Visual C# Samples, Specifications, Quick Reference and Visual C# General FAQ

http://social.msdn.microsoft.com/Forums/en-US/csharpgeneral/thread/2d666562-ed08-4461-bf92-7808913b4e96

Number to Text in console Program

namespace Number2Text01
{
    class Program
    {
        static string str;
        static void Main(string[] args)
        {
            Console.Write("\n Enter Three Digit number::");
            int amt = int.Parse(Console.ReadLine());
            int temp,i;
          //static string str;
            string[] Hundreds = new string[] { "One Hundred", "Two hundred", "Three Hundreds", "Four Hundreds", "Five hundred", "Six hundred", "Seven Hundreds", "Eight hundred", "Nine hundred" };
            string[] Tens = new string[] { "", "Ten", "Twenty", "Thirty", "Fourty", "Fifty", "Sixty", "Seventy", "Eight", "Ninty" };
            string[] Ones = new string[] {"","One","Two","Three","Four","Five","Six","Seven","Eight","Nine" };
                        
            int[] arr = new int[3];
            temp=amt;
            i = 0;
            while (temp != 0)
            {
                arr[i] = (temp % 10);
                temp = temp / 10;
                i++;
            }
            i -= 1;
            while (i != -1)
            {
                if (i == 2)
                    str = Hundreds[arr[i]-1];
                if (i == 1)
                    str += " and " + Tens[arr[i]];
                if (i == 0)
                    str +=" " + Ones[arr[i]];                            
                i--;
            }
            Console.WriteLine("\n\t Given number is "+amt+" and the Text is  "+str);
            Console.Read();
        }
    }
}

Number to Text1

namespace Number2Text1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            string[] ones ={"One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen" };
            string[] tens ={ "Ten", "Twenty", "Thirty", "Fourty", "Fifty", "Sixty", "Seventy", "Eighty", "Ninty" };
            string[] hundreds = { "One hundred", "Two hundred", "Three hundred", "Four hundred", "Five hundred", "Six hundred", "Seven hundred", "Eight hundred", "Nine hundred" };
            int Val, i;
            string Res = " ";
            Val = Convert.ToInt32(textBox1.Text);
            if (Val > 999 && Val < 10000)
            {
                i = Val / 1000;
                Res = ones[i-1] + " Thousand ";
                Val = Val % 1000;
            }
            if (Val > 99 && Val < 1000)
            {
                i = Val / 100;
                Res = Res + hundreds[i - 1];
                Val = Val % 100;
            }
            if (Val > 19 && Val < 100)
            {
                i = Val / 10;
                Res = Res + tens[i-1];
                Val = Val % 10;
            }
            if (Val > 0 && Val < 20)
            {
                Res = Res + ones[Val-1];
                textBox2.Text = Res;
            }
            textBox2.Text = Res;
        }

        private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
        {
            if (((e.KeyChar > 47 && e.KeyChar < 58)||(e.KeyChar ==8)) != true)
                e.Handled = true;
        }

      private void button3_Click(object sender, EventArgs e)
        {
            textBox1.Clear();
            textBox2.Clear();
            textBox1.Focus();
        }
    }
}