Keep text positions after saving richtextbox to RTF file

Question

i'm trying to create some RTF files from richtextbox content ( which is load from RTF files ) After opening file by some code and applying some changes and saving back new file (output) to another location. i find that positions text have changed and also font colors. please see attached captures for more clarifications. input:

output:

desired ouput

I think i need to talk a bit about what i apply to input from the code: well i need to replace every variables begining by $ by some variables from databases:

I used this portion of code for that:

foreach (Match match in Regex.Matches(richTextBox1.Text, "(\\$\\w+)"))
                    {
                        if (match.Groups[1].Value.Substring(1).Equals("Add1"))
                            richTextBox1.Text = richTextBox1.Text.Replace(match.Groups[1].Value, getAdress1(nums_res[j].ToString()));
                        if (match.Groups[1].Value.Substring(1).Equals("Add2"))
                            richTextBox1.Text = richTextBox1.Text.Replace(match.Groups[1].Value, getAdress2(nums_res[j].ToString()));
                        if (match.Groups[1].Value.Substring(1).Equals("Add3"))
                            richTextBox1.Text = richTextBox1.Text.Replace(match.Groups[1].Value, getAdress3(nums_res[j].ToString()));
                        if (match.Groups[1].Value.Substring(1).Equals("Add4"))
                            richTextBox1.Text = richTextBox1.Text.Replace(match.Groups[1].Value, getLand(nums_res[j].ToString()));
                        if (match.Groups[1].Value.Substring(1).Equals("Rechnr"))
                            richTextBox1.Text = richTextBox1.Text.Replace(match.Groups[1].Value, nums_res[j]);
                        if (match.Groups[1].Value.Substring(1).Equals("Datum"))
                            richTextBox1.Text = richTextBox1.Text.Replace(match.Groups[1].Value, getDatum(nums_res[j].ToString()));
                        if (match.Groups[1].Value.Substring(1).Equals("resname"))
                            richTextBox1.Text = richTextBox1.Text.Replace(match.Groups[1].Value, getName1(nums_res[j].ToString()));
                        if (match.Groups[1].Value.Substring(1).Equals("resvorname"))
                            richTextBox1.Text = richTextBox1.Text.Replace(match.Groups[1].Value, getVorname(nums_res[j].ToString()));
                        if (match.Groups[1].Value.Substring(1).Equals("resroom"))
                            richTextBox1.Text = richTextBox1.Text.Replace(match.Groups[1].Value, getZimmer(nums_res[j].ToString()));
                        if (match.Groups[1].Value.Substring(1).Equals("anz"))
                            richTextBox1.Text = richTextBox1.Text.Replace(match.Groups[1].Value, getAnz(nums_res[j].ToString()));
                    }

                    int indexToText = richTextBox1.Find(getAdress1(nums_res[j].ToString()));
                    int endIndex = richTextBox1.Find(getAdress1(nums_res[j].ToString()));
                    if(indexToText > 0 && endIndex > 0)
                        richTextBox1.Select(indexToText, endIndex); richTextBox1.SelectionAlignment = System.Windows.Forms.HorizontalAlignment.Center;

                    int indexToText2 = richTextBox1.Find(getLand(nums_res[j].ToString()));
                    int endIndex2 = richTextBox1.Find(getLand(nums_res[j].ToString()));
                    if (indexToText2 > 0 && endIndex2 > 0)
                        richTextBox1.Select(indexToText2, endIndex2);  richTextBox1.SelectionAlignment = System.Windows.Forms.HorizontalAlignment.Center;
                    richTextBox1.SaveFile("d:\\ryadmogadoroutput" + nums_res[j].ToString());
                    i = i + 1;
                    richTextBox1.Clear();

for now i dont replace all of them but just some and i want to know where the difference comes between my output and desired output. ( as u can see, i tried to center first variables from the code)

i'm wondering if theres a way to keep original format of the file after applying the changed i talked about

Thank you

EDIT: After changing the property .text to rtf here the improved output. still some details to fix: font color, and some deplaced ( i dont know why ) strings, please see date:$datum

EDIT: solution suggestion by @TaW: output:

compilation error:

Answer 1

I Think you should change the text format to RTF Format by changing "richTextBox1.Text" to "richTextBox1.RTF"

Answer 2

You must never change the Text directly after any formatting has been applied to the RichText. Instead you need to work strictly on the SelectedText using Copy, Paste, Append and the other specialized methods.

So at the very least you need to write an appropriate Replace function!

Maybe, with a little luck, not working on the Text but the Rtf property will also help, but it may be interwoven with formatting stuff that might be in the way..

Here is a function that will to do it :

void RtfReplace(RichTextBox RTB, Match match, string replace,  ref int offset)
{
    RTB.Select(match.Index + offset, match.Length);
    RTB.SelectedText = replace;
    offset += replace.Length - match.Length;
}

And a few respective calls

int offset = 0;
foreach (Match match in Regex.Matches(richTextBox1.Text, "(\\$\\w+)"))
{
    if (match.Groups[1].Value.Substring(1).Equals("Add1"))
        RtfReplace(richTextBox1, match, getAdress1(nums_res[j].ToString()), ref offset); 
    if (match.Groups[1].Value.Substring(1).Equals("Add2"))
        RtfReplace(richTextBox1, match, getAdress2(nums_res[j].ToString()), ref offset); 
    //..

Update: Since each replacement is likely to change the length of the replaced piece of text we will need to adjust all positions in the matches collection by that difference (or repeatedly call the whole replacement code until no more matches are found.) The fix is simple, though..