我正在尝试使用 C# 从 winform 文本框中将 NULL 值插入到数字数据库字段中。我正在创建一个应用程序来将生产数据输入数据库。数量变量设置为int?接受 null 因为如果一件设备坐下就不会输入任何值。数据库字段的默认值也设置为 Null。我怎样才能将文本框留空并在数据库字段中输入 Null?我已缩减我的代码以包含受影响的内容。
private void btnInsert_Click(object sender, EventArgs e)
{
int? runQty = 0;
int? scrapQty = 0;
try
{
dbConn = new OleDbConnection();
dbConn.ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + ch + strDataFilePath + ch;
dbConn.Open();
sql = "INSERT INTO DailyProduction (runQty, scrapQty)" +
"Values (@runQty, @scrapQty)";
dbCmd = new OleDbCommand(sql, dbConn);
if (runQty.HasValue)
{
runQty = Convert.ToInt16(this.runQuatity.Text);
dbCmd.Parameters.Add("@runQty", OleDbType.Numeric).Value = runQty;
}
else
{
runQty = null;
dbCmd.Parameters.Add("@runQty", OleDbType.Numeric).Value = runQty;
}
if (scrapQty.HasValue)
{
scrapQty = Convert.ToInt16(this.scrapQuantity.Text);
dbCmd.Parameters.Add("@scrapQty", OleDbType.Numeric).Value = scrapQty;
}
else
{
scrapQty = null;
dbCmd.Parameters.Add("@scrapQty", OleDbType.Numeric).Value = scrapQty;
}
dbCmd.Connection.Close();
dbConn.Close();
MessageBox.Show("Record Entered!");
}
catch (Exception err)
{
MessageBox.Show("Error: " + err.Message.ToString());
}
}
最佳答案
你可以这样做:
var runQty = string.IsNullOrEmpty(this.runQuatity.Text)
? DBNull.Value
: Convert.ToInt16(this.runQuatity.Text);
dbCmd.Parameters.Add("@runQty", OleDbType.Numeric).Value = runQty;
var scrapQty = string.IsNullOrEmpty(this.scrapQuantity.Text)
? DBNull.Value
: Convert.ToInt16(this.scrapQuantity.Text);
dbCmd.Parameters.Add("@scrapQty", OleDbType.Numeric).Value = scrapQty;
关于c# - 如何将 int NULL 插入数字数据库字段?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/35614227/