WinForm中设置NumericUpDown控件Increment为0.01M后数值增减无效果的技术问题

Got it, let's break down why your controls aren't behaving as expected and fix it right away.

The core issue here is two-fold:

• You didn't set the DecimalPlaces property for your NumericUpDown controls (it defaults to 0, meaning only integers are displayed)
• You forgot to apply the 0.01 increment to your second control (t2)

Even though you set Increment = 0.01M for t, the control was only showing whole numbers—so when you clicked the up/down arrows, the value was changing behind the scenes, but you couldn't see it.

Here's your revised code with the necessary fixes:

namespace Proiect1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        int i = 1;
        int o = 1;
        private void button1_Click(object sender, EventArgs e)
        {
            Label l = new Label();
            Label l2 = new Label();
            NumericUpDown t = new NumericUpDown();
            NumericUpDown t2 = new NumericUpDown();
            l.Top = i * 25;
            l.Left = 3;
            l2.Top = i * 25;
            l2.Left = 63;
            
            // Configure first NumericUpDown
            t.Value = 0;
            t.Increment = 0.01M;
            t.DecimalPlaces = 2; // Critical: enables display of two decimal places
            t.Top = i * 25;
            t.Left = 30;
            t.Size = new System.Drawing.Size(60, 30); // Wider to fit decimal digits
            
            // Configure second NumericUpDown (added missing Increment and DecimalPlaces)
            t2.Value = 0;
            t2.Increment = 0.01M; // Apply the same 0.01 step here
            t2.DecimalPlaces = 2; // Match decimal display for consistency
            t2.Top = i * 25;
            t2.Left = 90;
            t2.Size = new System.Drawing.Size(60, 30); // Wider to fit decimal digits
            
            i++;
            l.Size = new System.Drawing.Size(25, 20);
            l2.Size = new System.Drawing.Size(29, 20);
            l.Text = "n" + o;
            l2.Text = "w" + o;
            o++;
            panel1.Controls.Add(t);
            panel1.Controls.Add(t2);
            panel1.Controls.Add(l);
            panel1.Controls.Add(l2);
            panel1.AutoScroll = true;
        }
    }
}

Key Explanations: #

• DecimalPlaces = 2: This tells the control to display two digits after the decimal point, so you'll actually see the 0.01 increments when using the up/down arrows.
• Added t2.Increment = 0.01M: Your original code only set the increment for t, leaving t2 with the default increment of 1. Now both controls will use the 0.01 step.
• Widened control size: Increasing the Size to 60px wide ensures the full decimal value is visible without being truncated.

Give this a run, and both NumericUpDown controls should now increment/decrement smoothly by 0.01 when you use the arrow buttons.

内容的提问来源于stack exchange，提问作者DariusMan