Insert user-defined number of spaces before and after a line using C #

Question

I use a line builder to format my line to add and add white spaces at the beginning and end of a line

here is what i still have:

private void button1_Click(object sender, EventArgs e) { String Word = textBox1.Text; AppendPrependText(Word); } private void AppendPrependText (String Word) { int count = Convert.ToInt32(textBox2.Text); int WordCount = Word.Count(); int totalChar = count + WordCount; string format = "{-"+totalChar+ "," +totalChar+ "}"; StringBuilder sb = new StringBuilder(); sb.AppendLine(string.Format(format, Word)); textBox3.Text = sb.ToString(); } 

but I get the wrong format of the error. What am I doing wrong?

Answer 1

I think you do not need to use a separate operation to format the string, you can use the .AppendFormat() method of the StringBuilder Class . Here is a sample code for you:

 StringBuilder sbAppendFormat = new StringBuilder(); int numberOfSpaces=0; if(int.TryParse(textBo2.Text, out numberOfSpaces)) { string whiteSpaceSequence= new string(' ',numberOfSpaces); sbAppendFormat.AppendFormat("{0}{1}{0}", whiteSpaceSequence, "This is your String"); } textBox3.Text = sbAppendFormat.ToString(); 

Note. - Suppose you need to add some white spaces (let it be 5 ) before and after a certain word.

Answer 2

There are two questions. First, you use StringBuilder to format the string, which reduces the overhead caused by concatenation, but you also do additional concatenation in the local variable format .

The second problem is that your format string is incorrect: it does not include the argument index. Your method expects a single word, so the index must be zero before the fill command.

Fortunately, you can skip the concatenation of a format string and simply add your user space (or any other character) to a new instance of StringBuilder

Answer 3

There are some errors in your code:

Format Exception will be precisely set by this line:

 sb.AppendLine(string.Format(format, Word)); 

Your current format does not contain {0} in which the Word value should be replaced.

 //you should put here somewhere {0} in the format or remove the Word for string.Format //for an example string format = "{-" + totalChar + "," + totalChar + "}{0}"; 

Also this line is possible with a Format Exception if textBox2.Text for example a11:

 int count = Convert.ToInt32(textBox2.Text); 

You need to use int.TryParse

 int count = 0; int.TryParse(textBo2.Text, out count); 

Answer 4

What is the problem:

 string format = "{-"+totalChar+ "," +totalChar+ "}"; 

Let them say if totalChar = 10; than

 format = "{-10,10}" 

which is not a valid format, whereas it should be

 {0,10}{1,10} 

and therefore your line will look like

 Console.WriteLine(string.Format("{0,10}{1,10}", "Mohit","")); 

The third argument was intentionally left blank so that nothing is printed after the word. but you will have 10 spaces.

But I would recommend you use String.PadRight and String.PadLeft .

An example of demonstrating your task with PadLeft and PadRight

 int count = 5; string st = "mohit "; int WordCount = st.Count(); int totalChar = count + WordCount; st = st.PadRight(totalChar, ' '); st = st.PadLeft(totalChar + count, ' '); Console.WriteLine(st); 

Answer 5

To simply add spaces or characters, front and / or back, Padding will work just fine.

 private void button1_Click(object sender, EventArgs e) { int amount; int.TryParse(textBox2.Text, out amount); var str = textBox1.Text.PadLeft(amount + textBox1.TextLength); str = str.PadRight(amount + str.Length); textBox3.Text = str; } 

Then you can select spacer (paddingChar) also later, if necessary / required

 var str = textBox1.Text.PadLeft(amount + textBox1.TextLength, '>'); str = str.PadRight(amount + str.Length, '<'); 

Additionally with an additional method:

 private void button1_Click(object sender, EventArgs e) { textBox3.Text = Format(textBox1.Text, textBox2.Text); } private string Format(string word, string spaces) { int amount; int.TryParse(spaces, out amount); var str = word.PadLeft(amount + word.Length); str = str.PadRight(amount + str.Length); return str; } 

Answer 6

I did not use StringBuilder , I returned String from AppendPrependText . The if statement checks for invalid integer input in textBox2 if its invalid returns the original string. If this is a valid integer, create a padString space with count , then return the original string placed between the two of the padStrings .

EDIT: Added checking for negative numbers by adding AND count > 0 to the if statement.

 private String AppendPrependText(String Word) { int count = 0; if (int.TryParse(textBox2.Text, out count) && count > 0) { String padString = "".PadLeft(count, ' '); return padString + Word.ToString() + padString; } else { return Word; } } private void button1_Click_1(object sender, EventArgs e) { String Word = textBox1.Text; textBox3.Text = ">" + AppendPrependText(Word) + "<"; }