CODEWITHSUNDEEP
c#winformstextbox
Oscar Arango
Oscar Arango

Reputation: 113

Allow only integers in TextBoxes

I'm having a problem with checking textboxes and making sure there's only integers in them.

So far I'm able to confirm that there's text in the textboxes, but checking if they're integers isn't working. Here's my code that so far works.

if (textBox1.Text.Length == 0)
{
    errorProvider1.SetError(textBox1, "need Cost of Disks");
    return;
}
if (textBox2.Text.Length == 0)
{
    errorProvider2.SetError(textBox2, "need Total disks in package");
    return;
}
if (textBox3.Text.Length == 0)
{
    errorProvider3.SetError(textBox3, "need the Gigabyte per disk");
    return;
}
try
{
    Double[] myValues = new Double[3];
    myValues[0] = Double.Parse(textBox1.Text);
    myValues[1] = Double.Parse(textBox2.Text);
    myValues[2] = Double.Parse(textBox3.Text);

    Double ppd = myValues[0] / myValues[1] / myValues[2];

    ppd = Math.Round(ppd, 3, MidpointRounding.AwayFromZero);

    label4.Text = ppd.ToString();
}
catch (FormatException)
{
    //errorProvider1.SetError(label4, "testing1");

    //errorProvider2.SetError(label4, "testing2");

    //errorProvider3.SetError(label4, "testing3");
    return;
}

Upvotes: 2

Views: 10802

Answers (6)

LOZ
LOZ

Reputation: 1177

If you ever start using ajax tool kit, keep this for your records

<ajaxToolkit:FilteredTextBoxExtender ID="FilteredTextBoxExtender1" TargetControlID="FUND_CD" FilterType="Custom" ValidChars="1234567890" runat="server">
                        </ajaxToolkit:FilteredTextBoxExtender>

Upvotes: -1

Daniel Mošmondor
Daniel Mošmondor

Reputation: 19956

If you don't want to permit ANYTHING except numbers into the editbox, hook into keyboard events, check for characters that aren't digits and cancel them out.

When you sort out what events are needed on one textbox, just reuse same event on others, since you don't have to copy events around.

Upvotes: 0

naspinski
naspinski

Reputation: 34689

Using your current pattern, something like this:

int tester;
if (!Int32.TryParse(textBox1.Text, out tester))
{
    errorProvider1.SetError(textBox1, "must be integer");
    return;
}

Upvotes: 2

Stu
Stu

Reputation: 15769

Why don't you use a MaskedTextBox?

Upvotes: 1

hspain
hspain

Reputation: 17568

You can use the int.TryParse method to check if the string is an integer:

int n = 0;
bool isNumber = int.TryParse(textBox1.Text, out n);

if (!isNumber)
   return;

Upvotes: 0

David B
David B

Reputation: 2698

Override the Validating event in your form's textboxes and then you can do a TryParse on the contents.

public void textBox1_Validating(...)
{
  // TryParse
}

Upvotes: 0

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