Default value of textbox

How to set value of textbox?

I have this 1 textbox, and i want to set the default value is 0 so that when user not entering anythng my calculation still can.

Answers:

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Method 1

This can either be done in the markup (.aspx) like:

<asp:TextBox id="txt" runat="server" Text="0" />

Or in the code-behind (.aspx.cs):

txt.Text = 0;

Or if you’re using VB.NET:

txt.Text = 0

However, if you’re doing a calculation based on this, you shouldn’t rely on there always being a value in the textbox.

You could do:

Dim txtValue as Integer = 0
If IsNumeric(txt.Text) Then
   txtValue = txt.Text
End If

Method 2

If you want to use it with numbers, then you can tell the textbox that it should be with numbers, then “0” will be default.

<asp:TextBox ID="TB_Numbers" TextMode="Number" Text="0" runat="server"></asp:TextBox>

Method 3

As Curt mentioned, you can put default value directly in asp control or in code behind however if you don’t wish to show a 0 in textbox always then once you call the calculation method you can do something like this.

short valueForTextBox1;
if(txt.Text == String.Empty)
{
txt.Text = 0;
valueForTextBox1 = 0;
}
else
{
if(Int16.TryParse(txt.Text, out valueForTextBox1))
{
//Do Calculation
}
else
{
//Show some error that user has entered invalid value.
}
}

This will help the user understand that they left some boxes empty when a zero will appear in them as calculation is called. Hope this helps

Method 4

Just use this on the line of the textbox control to populate your date and time and make not visible if you want 

Value='<%# Now()%>'

Method 5

Converting a String into a Number – in your case the value available in textbox.

var val1 = Number(document.getElementById("TextBox1").value);

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0