删除文本框绑定的最后一个字符

Question

I am running into some problem binding a textbox to a property in my view. The binding works perfectly until I try to remove the last character. The cursor moves back but the last character is still there in the textbox and in the property it is bind to.

<TextBox Grid.Column="0" Text="{Binding SearchText, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>

And the Propety itself

    public string SearchText
    {
        get { return _searchText; }
        set 
        {
            if (searchText != value)
            {
                if (value != "")
                {
                    Debug.WriteLine("Typed Value " + value);
                    searchText = value;
                }

            }
        }
    }

This outputs to: "Typed Value F" if I try to completely erase Foo from the textbox. On the last press of backspace, the cursor moves back but the character is not removed.

How could i solve this?

Answer 1

Your conditional statement prevents the new value from being set.

if (value != "") //if value is NOT an empty string
{
   Debug.WriteLine("Typed Value " + value);
   searchText = value;
}

Therefore when it is an empty string (ie last character deleted), you're not calling searchText = value therefore not setting the new value. I can't see a reason for having that check in the code you've shown so you can either remove it or make sure you're always setting the value outside that block.

Answer 2

Removing everything from TextBox means setting Text to string.Empty or "".

Now you dont let the property to be set to empty therefore your last character always stays in TextBox.

Just get ride of if (value != "")

Answer 3

Look at your code again

if (value != "")
{
   Debug.WriteLine("Typed Value " + value);
   searchText = value;
}

If value == "" searchText is not assigned'

if (value != "")
{
   Debug.WriteLine("Typed Value " + value);      
}
searchText = value;