[英]Save canvas as image in ASP.NET Core
我正在嘗試將javascript畫布blob圖像發送到ASP.NET Core 2.1中的控制器方法。 但我的字符串參數在方法中始終為null
。
這是我的JavaScript:
$(".btn").click(function(e) {
var image = document.getElementById("canvas").toDataURL("image/png");
image = image.replace('data:image/png;base64,', '');
$.ajax({
type: 'POST',
url: '@Url.Action("Add", "Home")',
data: { imageData: image },
ajaxasync: true,
contentType: 'application/json; charset=utf-8',
dataType: 'json',
success: function (msg) {
alert('Image saved successfully !');
}
});
});
這是我的控制器:
[HttpPost]
public JsonResult Add(string imageData)
{
try
{
var folderName = @"uploads/";
var webRootPath = _appEnvironment.WebRootPath;
var newPath = Path.Combine(webRootPath, folderName);
string fileNameWitPath = newPath + DateTime.Now.ToString().Replace("/", "-").Replace(" ", "- ").Replace(":", "") + ".png";
using (FileStream fs = new FileStream(fileNameWitPath, FileMode.Create))
{
using (BinaryWriter bw = new BinaryWriter(fs))
{
byte[] data = Convert.FromBase64String(imageData);
bw.Write(data);
bw.Close();
}
}
return new JsonResult("Success");
}
catch (Exception exception)
{
return new JsonResult("Error");
}
}
您只需要刪除此行
contentType: 'application/json; charset=utf-8'
原因是JQuery默認將作為data
參數傳遞的對象轉換為key1=value1&key2=value2&...
格式,這顯然是無效的json。 因此,您無需指定application/json
內容類型,ASP.NET Core將自動正確解析此數據。
但是,如果要使請求與json
內容類型一起使用,則需要執行以下操作
的JavaScript
var image = document.getElementById("canvas").toDataURL("image/png");
image = image.replace('data:image/png;base64,', '');
var data = JSON.stringify({ imageData: image }); //serializing object to json
$.ajax({
type: 'POST',
url: '@Url.Action("Add", "Home")',
data: data, //passing json string
ajaxasync: true,
contentType: 'application/json',
dataType: 'json',
success: function (msg) {
}
});
C#
public class Model
{
public string ImageData { get; set; }
}
[HttpPost]
public IActionResult Add([FromBody]Model model) { //..
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