"I want to get all data from textbox like maxvalue ,minimum value, range."
I think what you are asking is to get a range of values from a single textbox?
That is not normal. A text box should contain one value: the user enters that, and then moves to the next. When all are completed, you can then access each individual one, check it, and if all are valid, use them.
int maxValue = 0;
if (int.TryParse(inputMaxValue.Text, out maxValue))
{
if (maxValue < 9999)
{
}
else
{
}
}
else
{
}
Then repeat for minimum, and range.