C# – Validation on a mobile 6 phone

cwindows-mobile

How does one do validation on a mobile 6 phone? Like in asp.net they have like validation controls and in windows forms they have the the "error" control. Yet I don't see any of these in mobile 6.

Like when I write my validation checking if statements and a error is found what do people do? Show a popup message? Or how do they display the validation errors to the user?

Best Answer

Validation was left out of the Compact Framework. I believe you will have to roll your own. I think the best option is to extend controls like the Textbox and add a Validate method to them.

In order to roll your own you will want to impliment something like this

public interface IValidatable {
    public bool IsValid();
}

public class TextBoxRequired : Textbox, IValidatable {
    public bool IsValid() {
        return !string.IsNullOrEmpty(this.Text);
    } 
}

//
public static class ValidationHelper {
    public static bool IsFormValid(Form form) {
        //loop through all controls in the form
        //find IValidatable and call IsValid
    }
}

There are some libraries out there, but I have never used them

http://www.codeplex.com/ValidationFramework

Related Solutions

C# – Cross-thread operation not valid: Control accessed from a thread other than the thread it was created on

As per Prerak K's update comment (since deleted):

I guess I have not presented the question properly.

Situation is this: I want to load data into a global variable based on the value of a control. I don't want to change the value of a control from the child thread. I'm not going to do it ever from a child thread.

So only accessing the value so that corresponding data can be fetched from the database.

The solution you want then should look like:

UserContrl1_LOadDataMethod()
{
    string name = "";
    if(textbox1.InvokeRequired)
    {
        textbox1.Invoke(new MethodInvoker(delegate { name = textbox1.text; }));
    }
    if(name == "MyName")
    {
        // do whatever
    }
}

Do your serious processing in the separate thread before you attempt to switch back to the control's thread. For example:

UserContrl1_LOadDataMethod()
{
    if(textbox1.text=="MyName") //<<======Now it wont give exception**
    {
        //Load data correspondin to "MyName"
        //Populate a globale variable List<string> which will be
        //bound to grid at some later stage
        if(InvokeRequired)
        {
            // after we've done all the processing, 
            this.Invoke(new MethodInvoker(delegate {
                // load the control with the appropriate data
            }));
            return;
        }
    }
}

C# – How to make a textbox that only accepts numbers

Two options:

Use a NumericUpDown instead. NumericUpDown does the filtering for you, which is nice. Of course it also gives your users the ability to hit the up and down arrows on the keyboard to increment and decrement the current value.

Handle the appropriate keyboard events to prevent anything but numeric input. I've had success with this two event handlers on a standard TextBox:

private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
{
    if (!char.IsControl(e.KeyChar) && !char.IsDigit(e.KeyChar) &&
        (e.KeyChar != '.'))
    {
            e.Handled = true;
    }

    // only allow one decimal point
    if ((e.KeyChar == '.') && ((sender as TextBox).Text.IndexOf('.') > -1))
    {
        e.Handled = true;
    }
}

You can remove the check for '.' (and the subsequent check for more than one '.') if your TextBox shouldn't allow decimal places. You could also add a check for '-' if your TextBox should allow negative values.

If you want to limit the user for number of digit, use: textBox1.MaxLength = 2; // this will allow the user to enter only 2 digits

Best Answer

Related Solutions

C# – Cross-thread operation not valid: Control accessed from a thread other than the thread it was created on

C# – How to make a textbox that only accepts numbers

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