无法将参数值从字符串转换为字节[]

debugcn 发表于 Dev

极酷

net 代码，当我尝试以二进制格式插入字符串时，我正面临这个问题。

我在decal.DecalLogoFileName 和decal.DecalLogoFileName 中有图像的二进制格式定义了一个字符串，所以当我尝试作为

cmd.Parameters.Add(new SqlParameter("@DecalLogoFileName", SqlDbType.Binary)).Value=decal.DecalLogoFileName;

decal.DecalLogoFileName="data:image/jpeg;base64,/9j/4AAQSkZJRgABAQAAAQABAAD/2wCEAAkGBxITEhUTExIWFhUXGB8aGBcYGR0ZHxobGhoXHRcYGBkaHyghHRolHRcXIjEhJSkrLi4uGB8zODMtNygtLisBCgoKDg0OGhAQGy0lHyUtLS0tLS0tLS0tLS0tLy0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLSstLS0tLS0tLS0tLf/AABEIALcBEwMBIgACEQEDEQH/xAAbAAACAwEBAQAAAAAAAAAAAAAEBQIDBgABB//EAEgQAAIBAgQDBQQHBQYDCAMAAAECEQADBBIhMQVBUQYTImFxMoGRoSNCUrHB0fAUcpLS4QczU2KCshVUc0Njg5OiwuLxFiRk/8QAGQEAAwEBAQAAAAAAAAAAAAAAAQIDAAQF/8QALBEAAgICAgECBQQCAwAAAAAAAAECERIhAzFBE2EiMlFxgUKhsdEEkSMzUv/aAAwDAQACEQMRAD8A"

我是贴花中的字符串值

function readURL(input) {
if (input.files && input.files[0]) {
        var reader = new FileReader();
        reader.onload = function (e) {
            $('#DecalLogo').attr('src', e.target.result);
            $('#hdImageName').val(e.target.result);
        }
        reader.readAsDataURL(input.files[0]);
    }
}

这里 hdImageName 值存储在 decal.DecalLogoFileName 中

我也试过

cmd.Parameters.Add(new SqlParameter("@DecalLogoFileName", SqlDbType.Binary)).Value=Convert.toByte(decal.DecalLogoFileName);

但是转换问题来了。

DecalLogoFileName 的列数据类型设置为 varbinary(MAX)

幸运的

像这样尝试；

var byteArray = Encoding.ASCII.GetBytes(decal.DecalLogoFileName);
cmd.Parameters.Add(new SqlParameter("@DecalLogoFileName", SqlDbType.VarBinary, byteArray.Length)).Value=byteArray;

要从数据库中检索图像，您可以使用Encoding.ASCII.GetString(byteArray). 然后你可以像这样把图片放到img src中；

        <img src="data:image/jpeg;base64,/9j/4AAQSkZJRgABAQAAAQABAAD/2wCEAAkGBxITEhUTExIWFhUXGB8aGBcYGR0ZHxobGhoXHRcYGBkaHyghHRolHRcXIjEhJSkrLi4uGB8zODMtNygtLisBCgoKDg0OGhAQGy0lHyUtLS0tLS0tLS0tLS0tLy0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLSstLS0tLS0tLS0tLf/AABEIALcBEwMBIgACEQEDEQH/xAAbAAACAwEBAQAAAAAAAAAAAAAEBQIDBgABB//EAEgQAAIBAgQDBQQHBQYDCAMAAAECEQADBBIhMQVBUQYTImFxMoGRoSNCUrHB0fAUcpLS4QczU2KCshVUc0Njg5OiwuLxFiRk/8QAGQEAAwEBAQAAAAAAAAAAAAAAAQIDAAQF/8QALBEAAgICAgECBQQCAwAAAAAAAAECERIhAzFBE2EiMlFxgUKhsdEEkSMzUv/aAAwDAQACEQMRAD8A" 
        alt="SampleImage" />

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