06 实现判断小数点输入位置的四则运算器
发布时间:2016-12-24 16:00:09
1 private void txtNumber1_KeyPress(object sender, KeyPressEventArgs e) 2 { 3 //MessageBox.Show(((int)(e.KeyChar)).ToString()); //A ...
1 private void txtNumber1_KeyPress(object sender, KeyPressEventArgs e) 2 { 3 //MessageBox.Show(((int)(e.KeyChar)).ToString()); //ASCii查看 4 //由于本事件可能有多个文本框的触发,所以要通过sender来得到触发该事件的控件 5 TextBox currentTextBox = sender as TextBox; 6 7 if (e.KeyChar < '0' || e.KeyChar > '9') 8 { 9 e.Handled = true;10 }11 if (e.KeyChar == 46)//让用户可以输入小数点12 {13 //检测这个number1文本框中是否已经包含小数点14 if (currentTextBox.Text.IndexOf(".") == -1)15 {16 //光标不能在第一位,也就是说小数点不能出现在第一位17 if (currentTextBox.SelectionStart > 0)18 {19 e.Handled = false;20 }21 }22 }23 if (e.KeyChar == 8) //让用户可以输入退格键24 {25 e.Handled = false;26 }27 28 }29 30 private void btnResult_Click(object sender, EventArgs e)31 {32 try33 {34 double number1 = Convert.ToDouble(txtNumber1.Text);35 double number2 = Convert.ToDouble(txtNumber2.Text);36 37 switch (comboBox1.Text)38 {39 case "加":40 lbResult.Text = (number1 + number2).ToString();41 break;42 case "减":43 lbResult.Text = (number1 - number2).ToString();44 break;45 case "乘":46 lbResult.Text = (number1 * number2).ToString();47 break;48 case "除":49 lbResult.Text = (number1 / number2).ToString();50 break;51 }52 }53 catch(Exception ex)54 {55 MessageBox.Show("你的输入有问题"+ex.Message);56 }57 }58 59 private void txtNumber1_TextChanged(object sender, EventArgs e)60 {61 lbResult.Text = " "; 62 }63 64 private void frmFourOperations_Load(object sender, EventArgs e)65 {66 comboBox1.SelectedIndex = 0; //当combobox的dropdownstyle属性设置为list时 将无法在属性写入初始值 需要通过该语句实现67 }
原标题:06 实现判断小数点输入位置的四则运算器
关键词:位置
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