无法将参数值从 String 转换为 Byte[]

Question

net 代码，当我尝试以二进制格式插入字符串时遇到这个问题。

我在 decal.DecalLogoFileName 中有图像的二进制格式并且 decal.DecalLogoFileName 定义了一个字符串所以当我尝试

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"

我在贴花中的字符串值为

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]);
    }
}

这里的 hdImageName 值存储在 decal.DecalLogoFileName

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)

Answer 1

这样试试；

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) 将其转换为base64 字符串。然后你可以像这样把图像放在img src中；

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

无法将参数值从 String 转换为 Byte[]

Failed to convert parameter value from a String to a Byte[]

c#

asp.net

ado.net

varbinarymax