Removing a character from my stringbuilder [duplic

问题:

This question already has answers here:

Best way to remove the last character from a string built with stringbuilder (11 answers)

Closed last year.

I am having the following string builder as msrtResult, which is quite long:

mstrResult.Append(rtbResult.Text).Append("})})" + Environment.NewLine)

How can I remove the last "," from mstrResult Now? (it is in the middle of that mstrResult and it is not the last character of the whole string since I am appending strings to it) I should do it before adding the newline. Thanks

回答1:

You can just decrease the length to shorten the string (C#):

mstrResult.Length -= 1;

EDIT:

After you updated you question, I think I know what you want :) How about this:

mstrResult.Append(rtbResult.Text).Append("})})" + Environment.NewLine);
var index = mstrResult.ToString().LastIndexOf(',');
if (index >= 0)
    mstrResult.Remove(index, 1);

回答2:

Add a StringBuilder extension.

public static StringBuilder RemoveLast(this StringBuilder sb, string value)
{
    if(sb.Length < 1) return sb;
    sb.Remove(sb.ToString().LastIndexOf(value), value.Length);
    return sb;
}

then invoke:

yourStringBuilder.RemoveLast(",");

回答3:

You can use StringBuilder.Remove() if you know the position of the character(s) you want to remove.

I'd imagine that it would be easier not to add it in the first place.

---

Your updated question talks about removing the last comma character. I'm guessing you want to do this to avoid creating a message that looks like this:

My shopping list contained milk, eggs, butter, and fish.

You'd assemble this in a loop, iterating over an array. Usually you can write the loop so that you simply choose (e.g. with an if statement) not to add the command when you are in the final iteration of the loop.

回答4:

To just remove the last character you appended use below: (This is VB but C should work similarly)

Dim c As New StringBuilder
c.Remove(c.Length - 1, 1)

回答5:

Try

mstrResult.Remove( mstrResult.Length - 1 - Environment.NewLine.Length
                 , Environment.NewLine.Length);

回答6:

Use:

stringbuilder blahh = new stringbuilder()
int searchKey = blahh.LastIndexOf(',');

then call

blahh.Remove( searchKey, 1).Insert(searchKey, " and"); or a blank.