The C # control textbox can only enter decimals (only one decimal point can be entered, only two digits, the first digit cannot be a decimal point)

 

<summary>///price and quantity input control (only one decimal point can be entered, only two digits can be input, first digit cannot be a decimal point)///</summary>///<param name= "E" > KeyPressEventArgs e</param>///<param name= "TextBox" >TextBox</param> public static void Keypressxs ( KeyPressEventArgs E, textbox textbox {if (char). Isnumber (E.keychar) | | E.keychar = = '. ' | | E.keychar = = (char) keys.back) {e.handled = false;//Let the action take effect int j = 0; int k = 0; bool flag = false; if (textBox.Text.Lengt H = 0) {if (E.keychar = = '. ') {e.handled = true;//Let Operation fail}} for (int i = 0; i < textBox.Text.Length i++) {if (textbox.text[i] = = '. ') {j + +; flag = true;} if (flag) {if (char). Isnumber (Textbox.text[i]) && E.keychar!= (char) keys.back) {k++;}} if (J >= 1) {if (E.keychar = = '. ') {e.handled = true;//Let Operation fail}} if (k = = 2) {if (char). Isnumber (Textbox.text[i]) && E.keychar!= (char) keys.back) {if (Textbox.text.length-textbox.selectionstart & Lt 3) {if (Textbox.selectedtext!= textbox.text) {e.handled = true;////Let actionInvalid}}}}/else {e.handled = true;}}

There's a problem.

First enter the integer part and then the whole part of the deletion, in disguise let the decimal point to the first place

In the case of a two-bit decimal, you cannot change a two-bit number if selected

Netizen Ymwcwee has corrected please refer to his code

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Http://blog.csdn.net/jzz870519/archive/2010/08/08/5796876.aspx, because I always failed to reply to the code, so I opened it myself ...

  View plain Copy to clipboard print? Private void textbox1_keypress (object sender, keypresseventargs e)    {        if  (char. Isnumber (E.keychar)  | |  e.KeyChar ==  '. '  | |  e.KeyChar ==  (char) keys.back | |  e.KeyChar ==  (char) keys.delete)        {            e.Handled = false;           //let the operation take effect               int  j = 0;                   //record number of decimal points            int k =  0;                   //Record decimal places            int dotloc = -1;             //Record decimal point position             bool flag = false;          // If there is a decimal point, let flag value true           //            //Remove First is 0 of the judgment, because we do not know the user's intention, maybe Ta next time to enter a number before the decimal point.            /*           if  (textbox1.text.length == 0)           {               if  (e.keychar ==  '.')               {                   e.handled = true;               }          }           */           //            for  (int i = 0; i < textbox1.text.length;  i++)            {                if  (textbox1.text[i] ==  '. ')                {                    j++;                    flag =  true;   &NBSP;&NBSP;&NBSP;&Nbsp;            dotloc = i;               }                   if  (flag)                 {                    if  (char. Isnumber (Textbox1.text[i])  && e.KeyChar !=  (char) keys.back && e. keychar !=  (char) keys.delete)                     {                        k++;                    }               }                  if  (j >=  1)                {                   if  (E. keychar ==  '. ')                    {                         if  (TextBox1.SelectedText.IndexOf ('. ')  == -1)                             e.Handled = true;          &nbsp   //enter "." and the selection does not have "." Operation Failure                     }               }                   if  (!flag)                    // This controls whether adding a decimal point when there is no decimal point satisfies two decimal places                 {                    if  (e.keychar ==  '. ')                    {                         if  (textbox1.text.length -  textbox1.selectionstart - textbox1.selectedtext.length > 2)          //the condition also can be instead of  " TextBox1.Text.Substring (Textbox1.selectionstart). Length-textbox1.selectionlength>2 "                             e.handled =  true;                    }               }                  if  (K&NBSP;==&NBSP;2)                {                    if&nbsp. (Textbox1.selectionstart > textbox1.text.indexof ('. ')  && textBox1.SelectedText.Length == 0 && e.KeyChar!      = (char) keys.delete && e.keychar!= (char) keys.back)        //If you already have two decimal places, the cursor is to the right of the decimal point,                        e.Handled = true;                }            }       }       else        {           e.Handled = true;        }   }  

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