I'm trying to make an if statement to check whether a TextBox has text it.
So something like this:
if (textbox1 has text)
{
//Then do this..
}
How would I write "textbox1 has text"?
if (textbox1.Text.Length > 0)
{
...
}
or
if (!string.IsNullOrEmpty(textbox1.Text))
{
...
}
You can get the text stored in the TextBox using Text property of the TextBox and then check whether it is null or empty like this :-
string text = textBox1.Text ;
if(String.IsNullOrEmpty(text))
{
// Do something
}
Check the length of the text box text.
if (textbox1.Text.Length > 0)
{
//do the process here
}
Please try
if(!string.IsNullOrWhiteSpace(textbox1.Text))
{
//
}
Checking the Length
if (textBox1.Text.Length > 0)
{
// perform task
}
Using the Null
if (!string.IsNullOrEmpty(textBox1.Text))
{
// perform a task
}
Using Trim would be nice for checking if a user is only putting spaces.
if (textBox1.Text.Trim().Length > 0)
{
// perform a task
}
Try any one of these and it should work. There are way more ways but since this question is a bit broad it's up to you.
Simple. Check out this MSDN page: string.IsNullOrEmpty
if (!string.IsNullOrEmpty(textBox1.Text))
{
}
Alternatively, you could use a property. This is especially helpful when you need to check multiple times to see if the textbox has text:
// a public property is not necessary for this
bool HasText
{
get
{
return !string.IsNullOrEmpty(textBox1.Text);
}
}
...
if (HasText)
{
}
Another way to go about doing this is by using an extension method:
public static class TextBoxUtility
{
public static bool HasText(this TextBox textBox)
{
return !string.IsNullOrEmpty(textBox.Text);
}
}
...
if(textBox1.HasText())
{
}
I prefer the latter instead of a property because it works across all textboxes.
the simpliest logic is this:
if (textBox1.Text != "")
MessageBox.Show("The textbox is not empty!");
else
MessageBox.Show("The textbox is empty!");
I have seen all the other answers on the page, suggesting solutions like
if (tb.Text == "")
{
// Is empty
} else {
// Is not empty
}
However this could easily break, and return that a text box is not empty, when it actually is. For example, a few spaces in the text box (and nothing else) would pass as not empty, when in fact, while not technically empty, you would probably want to report it as empty. A solution to this is the C# string.Trim() method. This removed all whitespace. Now changing my solution to this:
if (tb.Text.Trim() == "")
{
// Is empty
} else {
// Is not empty
}
... it would no longer report a text box full with spaces as not empty.
if(textBox1.Text!=null)
{
///code
}
or
if(textBox1.Text!=string.Empty)
{
//code
}
if(textbox.Text.Trim().Length > 0)
{
// Do something
}
Related
I have a checkedListBox where the user can select whatever they want to update. I want them to be able to freely update 1 up to 5 characteristics of a machine. So when they only want to update 1 thing, they do not have to provide the other 4 characteristics. Also, when they want to update 5 characteristics, they
can do it in one go. For that purpose I have the following if statements:
if (clbCharacteristicsToUpdate.CheckedItems.Count != 0)
{
if (clbCharacteristicsToUpdate.GetSelected(0))
{
currentITime = Convert.ToDouble(tbCurrentITime.Text);
MessageBox.Show(currentITime.ToString());
dh.UpdateCurrentITime(machineNr, currentITime);
}
if (clbCharacteristicsToUpdate.GetSelected(1))
{
cycleTime = Convert.ToDouble(tbCycleTime.Text);
MessageBox.Show(cycleTime.ToString());
dh.UpdateCycleTime(machineNr, cycleTime);
}
if (clbCharacteristicsToUpdate.GetSelected(2))
{
nrOfLinesPerCm = Convert.ToInt32(tbNrOfLinesPerCm.Text);
MessageBox.Show(nrOfLinesPerCm.ToString());
dh.UpdateNrOfLinesPerCm(machineNr, nrOfLinesPerCm);
}
if (clbCharacteristicsToUpdate.GetSelected(3))
{
heightOfLamallae = Convert.ToDouble(tbHeightOfLamallae.Text);
MessageBox.Show(heightOfLamallae.ToString());
dh.UpdateHeightOfLamallae(machineNr, heightOfLamallae);
}
if (clbCharacteristicsToUpdate.GetSelected(4))
{
if (rbLTB.Checked)
{
machineType = 2;
MessageBox.Show(machineType.ToString());
}
else if (rbSTB.Checked)
{
machineType = 1;
MessageBox.Show(machineType.ToString());
}
if(!rbLTB.Checked && !rbSTB.Checked)
{
MessageBox.Show("Select a machine type to update!");
return;
}
dh.UpdateType(machineNr, machineType);
}
}
My problem is that, when I choose and update 1 thing it works perfectly. But when I choose multiple ones, it only executes the last if statement that returns true. I thought about using if-else but then only the first one that returns true will be executed. I also thought about having if statements for each possibility. But since I have 5 characteristics I can update, this would make 25 possibilities and I do not want to have 25 if statements. Thanks in advance!
GetSelected does not check whether the item has been checked, but that it is actually selected.
For example, in the below image "Item 2" will will return true for GetSelected. It is selected, not checked.
Instead you could do something like checking the clbCharacteristicsToUpdate.CheckedItems property to get the items that are actually checked.
The GetSelected method actually comes from the ListBox class, which CheckedListBox inherits from.
Try this:
This is a helper method I created on a button.
private void button1_Click(object sender, EventArgs e)
{
CheckList();
}
This method looks if items are checked and iterates over the collection of checked ones, calling the last metod.
private void CheckList()
{
if (clbCharacteristicsToUpdate.SelectedItems.Count != 0)
{
foreach (int indexChecked in clbCharacteristicsToUpdate.CheckedIndices)
{
CheckSelectedItem(indexChecked);
}
}
}
And finally, here the appropriate actions are taken based on indexes.
private void CheckSelectedItem(int index)
{
if (index == 0)
{
//Do stuff on Zero
MessageBox.Show("Zero");
}
if (index == 3)
{
//Do stuff on One
MessageBox.Show("Three");
}
}
I am trying to create an if else statement to show a message box if no input.
If(textbox1.text==false)
{
messagebox.show("please fill in the boxes")
}
I have 16 different text box currently out, do i need to use an if else statement for each?
Pass all TextBoxes in the list and loop it
//Create list once in the constructor of main form or window
List<TextBox> list = new List<TextBox>()
//...
list.Add(textbox1);
list.Add(textbox2);'
//...
Then loop it
foreach(TextBox txt in list)
{
if(String.IsNullOrWhiteSpace(txt.Text))
{
messagebox.Show("please fill in the boxes");
break;
}
}
Update
If all textboxes expecting only number/double input then use TryParse for checking if value is valid
foreach(TextBox txt in list)
{
Double temp;
if(Double.TryParse(txt.Text, temp) == true)
{
//save or use valid value
Debug.Print(temp.ToString());
}
else
{
messagebox.Show("please fill in the boxes");
break;
}
}
You can not compare string with Boolean. textbox.text is a string data type.
try this, if you want to show different message for different textbox, you must use if-else statement for all texboxes.
If(textbox1.text=="")
{
messagebox.show("please fill in the boxes")
}
or
If(string.IsNullOrEmpty(textbox1.text) == true)
{
messagebox.show("please fill in the boxes")
}
for multiple textbox validation
Adding the handler to the textboxes is easily done with a foreach loop in the form constructor:
foreach(TextBox tb in this.Controls.OfType<TextBox>().Where(x => x.CausesValidation == true))
{
tb.Validating += textBox_Validating;
}
use validating event to handle it
private void textBox_Validating(object sender, CancelEventArgs e)
{
TextBox currenttb = (TextBox)sender;
if(currenttb.Text == "")
MessageBox.Show(string.Format("Empty field {0 }",currenttb.Name.Substring(3)));
e.Cancel = true;
else
{
e.Cancel = false;
}
}
String and Boolean aren't comparable, also you can check if all the textfields are empty like described in this post
if(this.Controls.OfType<TextBox>().Any(t => string.IsNullOrEmpty(t.Text)) {
//Textfield is empty
}
First of all, you have a type mismatch error in your question. The Text property of a TextBox is of string type, while the keyword false is of bool type. You can read more on types in here.
The fix to this issue would be:
If (!string.IsNullOrEmpty(textbox1.Text))
{
Messagebox.Show("please fill in the boxes")
}
Secondly, modern programming is all about DRY principle. So, the answer is no, you do not need to write the same piece of code for each of them.
You could actually do it at least two ways.
The first way would be to create some sort of collection of your textboxes (an array, for example). Then you would create a method to iterate over this collection like this:
private bool AllTextboxesAreFilled()
{
var textboxes = new TextBox[] { textBox1, textBox2, textBox3 };
return textboxes.All(textbox => !string.IsNullOrEmpty(textbox.Text));
}
And then call it like:
if (!AllTextboxesAreFilled())
{
MessageBox.Show("please fill in the boxes");
}
The second way would be to make these textboxes children of some control (a Panel, for example) and then iterate over these children. This way you don't need to create an additional collection (and to remember to add elements in it in case you need more textboxes):
private bool AllTextboxesAreFilled()
{
return holderPanel.Controls.OfType<TextBox>().All(textbox => !string.IsNullOrEmpty(textbox.Text));
}
The usage is the same as in the previous example.
I have short windows program I use to add information quickly. But now I'm trying to enhance it.
Was looking for a more efficient want to check for empty text boxes and if the box was empty to find which one it was and set the focus back to only that box. Currently I loop through all of them and check to see if any box was empty if it is just display a message. But have to look to see which box is missing text. Heres the code:
bool txtCompleted = true;
string errorMessage = "One or more items were missing from the form";
foreach(Control c in Controls)
{
if (c is TextBox)
{
if (String.IsNullOrEmpty(c.Text))
{
txtCompleted = false;
}
}
}
if (txtCompleted == false)
{
MessageBox.Show(errorMessage);
}
Your approach using foreach looks promising to me. Howver you can use LINQ as well
if(this.Controls.OfType<TextBox>().Any(t => string.IsNullOrEmpty(t.Text)) {
...
}
You can use the focus() method to set the focus to the empty text box.
Set the focus on the control while in your loop, then break when done.
foreach(Control c in Controls)
{
if (c is TextBox)
{
if (String.IsNullOrEmpty(c.Text))
{
txtCompleted = false;
c.Focus();
MessageBox.Show(errorMessage);
break;
}
}
}
To get a reference to the empty textbox you use almost the same solution as R.T. presents, but use FirstOrDefault instead:
var emptyTextBox = Controls.OfType<TextBox>().FirstOrDefault(t => string.IsNullOrEmpty(t.Text)
if (emptyTextBox != null)
{
// there is a textbox that has no Text set
// set focus, present error message etc. on emptyTextBox
}
I have about 20 text fields on a form that a user can fill out. I want to prompt the user to consider saving if they have anything typed into any of the text boxes. Right now the test for that is really long and messy:
if(string.IsNullOrEmpty(txtbxAfterPic.Text) || string.IsNullOrEmpty(txtbxBeforePic.Text) ||
string.IsNullOrEmpty(splitContainer1.Panel2) ||...//many more tests
Is there a way I could use something like an Array of any, where the array is made of the text boxes and I check it that way? What other ways might be a very convenient way in which to see if any changes have been made since the program started?
One other thing I should mention is there is a date time picker. I don't know if I need to test around that as the datetimepicker will never be null or empty.
EDIT:
I incorporated the answers into my program, but I can't seem to make it work correctly.
I set up the tests as below and keep triggering the Application.Exit() call.
//it starts out saying everything is empty
bool allfieldsempty = true;
foreach(Control c in this.Controls)
{
//checks if its a textbox, and if it is, is it null or empty
if(this.Controls.OfType<TextBox>().Any(t => string.IsNullOrEmpty(t.Text)))
{
//this means soemthing was in a box
allfieldsempty = false;
break;
}
}
if (allfieldsempty == false)
{
MessageBox.Show("Consider saving.");
}
else //this means nothings new in the form so we can close it
{
Application.Exit();
}
Why is it not finding any text in my text boxes based on the code above?
Sure -- enumerate through your controls looking for text boxes:
foreach (Control c in this.Controls)
{
if (c is TextBox)
{
TextBox textBox = c as TextBox;
if (textBox.Text == string.Empty)
{
// Text box is empty.
// You COULD store information about this textbox is it's tag.
}
}
}
Building on George's answer, but making use of some handy LINQ methods:
if(this.Controls.OfType<TextBox>().Any(t => string.IsNullOrEmpty(t.Text)))
{
//Your textbox is empty
}
public void YourFunction(object sender, EventArgs e) {
string[] txtBoxArr = { textBoxOne.Text, textBoxTwo.Text, textBoxThree.Text };
string[] lblBoxArr = { "textBoxOneLabel", "textBoxTwoLabel", "textBoxThreeLabel" };
TextBox[] arr = { textBoxOne, textBoxTwo, textBoxThree };
for (int i = 0; i < txtBoxArr.Length; i++)
{
if (string.IsNullOrWhiteSpace(txtBoxArr[i]))
{
MessageBox.Show(lblBoxArr[i] + " cannot be empty.");
arr[i].Focus();
return;
}
}
}
I have a class for writing a PDF doc via MigraDoc.
A function makes a call like this:
var p = row.Cells[1].AddParagraph();
p.AddLineBreak();
p.AddLineBreak();
_renderHtml(office["Address"], p.AddFormattedText());
The _renderHtml code looks like this:
private void _renderHtml(string html, FormattedText text)
{
_renderHtmlElement(
new Html.Parsable("dom", html),
text
);
}
The _renderHtmlElement code then does a series of checks for what HTML to actually handle. I'm thinking I should throw it into a switch case, but that doesn't really affect my question. So it looks like this:
private void _renderHtmlElement(Html.Element element, FormattedText text)
{
if ("p" == element.Type)
{
//do stuff
}
else if ("li" == element.Type)
{
//do stuff
}
else if ("b" == element.Type || "strong" == element.Type)
{
text = text.AddFormattedText(TextFormat.Bold);
}
else if ("i" == element.Type || "em" == element.Type)
{
text = text.AddFormattedText(TextFormat.Italic);
}
else if ("br" == element.Type || "em" == element.Type)
{
text.AddLineBreak();
}
else if ("text" == element.Type)
{
//do stuff
}
else if("sup" == element.Type)
{
FormattedText ft = text.AddFormattedText(element.ContentDecoded);
ft.Superscript = true;
}
foreach (var child in element.ChildElements)
{
_renderHtmlElement(child, text);
}
}
My piece is to get the superscript code working. The code I have in there now will add in the correct content, formatted as a superscript, but it then still has the original content (not superscripted) immediately following it. The methods of text seem to only allow add functions, there's no replace or substring or anything similar for me to just tear out the second instance.
Am I overlooking something obvious here? As you can see from the bold/italic examples, it's a fairly straight forward process, so I would think I'm just not passing in the text.superscript properly.
Any and all help would be greatly appreciated.
Cheers
You add the Superscript text, then you call _renderHtmlElement for the children - maybe a child gives you the same text, but without superscript attribute.
Are there other tags between <sup> and </sup> in your HTML?
MigraDoc has Remove methods so you can remove items - but better not to add them in the first place.
I'd put a breakpoint on "ft.Superscript = true;" and check what _renderHtmlElement does for the children of the "sup" element.