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file controls and image controls to implement a picture preview

Source: Internet
Author: User
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Two ways: 1. Using JS to achieve
2. Add a statement directly to the control's event-handling function (equivalent to writing the function code of JS directly here, as in the comment premises)
Note: You can use the <input type= ' file ' > can also be implemented with <asp:FileUpload>, although the latter does not onchange events, but when forced to use, although prompted [Validation ( asp.net): attribute ' onchange ' is not a valid attribute of element ' FileUpload '], but the desired effect can be achieved.

 
 
    
  
  
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  2. <body>
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  4. <script type= "Text/javascript" >
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  5. 
  
  6. function Ch (val)
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  7. 
  
  8. {
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  9. 
  
  10. document.getElementById (' Image1 '). Src=val;
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  11. 
  
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  13. 
  
  14. }
    15. 
  
  
  15. 
  
  16. </script>
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  17. 
  
  18. <form id= "Form1" runat= "Server" >
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  19. 
  
  20. <div>
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  22. <asp:image id= "Image1" runat= "Server" width= "135px"/>
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  23. 
  
  24. <%--<input id= "File1" type= "file" onchange= "document.getElementById (' Image1 '). Src=this.value"/>--%>
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  25. 
  
  26. <input id= "File1" type= "file" onchange= "ch (this.value);" />
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  27. 
  
  28. <asp:fileupload id= "FileUpload1" runat= "Server" onchange= "document.getElementById" (' Image1 '). Src=this.value "/ >
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  29. 
  
  30. </div>
    31. 
  
  
  31. 
  
  32. </form>
    33. 
  
  
  33. 
  
  34. </body>
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